Add specs dir

Currently we do not have a dib-specific specs repository. Technically,
we are part of the tripleo-specs repository but dib-core does not imply
tripleo-specs core. To fix this and to encourage the use of specs lets
create a specs process that lives right in tree.

Change-Id: I7bd7e9fa94635621590f72702107e218155fef2a

doc/source/specs/README.rst

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+=======
+README
+=======
+
+diskimage-builder Specifications
+================================
+
+
+This directory is used to hold approved design specifications for changes to
+the diskimage-builder project. Reviews of the specs are done in gerrit, using a
+similar workflow to how we review and merge changes to the code itself. For
+specific policies around specification review, refer to the end of this
+document.
+
+The layout of this directory is::
+
+  specs/v<major_version>/
+
+Where there are two sub-directories:
+
+- specs/v<major_version>/approved: specifications approved but not yet
+  implemented
+- specs/v<major_version>/implemented: implemented specifications
+- specs/v<major_version>/backlog: unassigned specifications
+
+The lifecycle of a specification
+--------------------------------
+
+Developers proposing a specification should propose a new file in the
+``approved`` directory. diskimage-builder-core will review the change in the
+usual manner for the project, and eventually it will get merged if a consensus
+is reached.
+
+When a specification has been implemented either the developer or someone
+from diskimage-builder-core will move the implemented specification from the
+``approved`` directory to the ``implemented`` directory. It is important to
+create redirects when this is done so that existing links to the approved
+specification are not broken. Redirects aren't symbolic links, they are
+defined in a file which sphinx consumes. An example is at
+``specs/v1/redirects``.
+
+This directory structure allows you to see what we thought about doing,
+decided to do, and actually got done. Users interested in functionality in a
+given release should only refer to the ``implemented`` directory.
+
+Example specifications
+----------------------
+
+You can find an example spec in ``specs/template.rst``.
+
+Backlog specifications
+----------------------
+
+Additionally, we allow the proposal of specifications that do not have a
+developer assigned to them. These are proposed for review in the same manner as
+above, but are added to::
+
+  specs/backlog/approved
+
+Specifications in this directory indicate the original author has either
+become unavailable, or has indicated that they are not going to implement the
+specification. The specifications found here are available as projects for
+people looking to get involved with diskimage-builder. If you are interested in
+claiming a spec, start by posting a review for the specification that moves it
+from this directory to the next active release. Please set yourself as the new
+`primary assignee` and maintain the original author in the `other contributors`
+list.
+
+Specification review policies
+=============================
+
+There are some special review policies which diskimage-builder-core will apply
+when reviewing proposed specifications. They are:
+
+Trivial specifications
+----------------------
+
+Proposed changes which are trivial (very small amounts of code) and don't
+change any of our public APIs are sometimes not required to provide a
+specification. The decision of whether something is trivial or not is a
+judgement made by the author or by consensus of the project cores, generally
+trying to err on the side of spec creation.

doc/source/specs/v1/approved/v1-template.rst

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+..
+ This work is licensed under a Creative Commons Attribution 3.0 Unported
+ License.
+
+ http://creativecommons.org/licenses/by/3.0/legalcode
+
+==============================================
+Example Spec - The title of your specification
+==============================================
+
+Introduction paragraph -- why are we doing anything? A single paragraph of
+prose that operators can understand. The title and this first paragraph
+should be used as the subject line and body of the commit message
+respectively.
+
+Some notes about the diskimage-bulider spec process:
+
+* Not all changes need a spec. For more information see
+  <add_url_here>
+
+* The aim of this document is first to define the problem we need to solve,
+  and second agree the overall approach to solve that problem.
+
+* This is not intended to be extensive documentation for a new feature.
+
+* You should aim to get your spec approved before writing your code.
+  While you are free to write prototypes and code before getting your spec
+  approved, its possible that the outcome of the spec review process leads
+  you towards a fundamentally different solution than you first envisaged.
+
+* But, API changes are held to a much higher level of scrutiny.
+  As soon as an API change merges, we must assume it could be in production
+  somewhere, and as such, we then need to support that API change forever.
+  To avoid getting that wrong, we do want lots of details about API changes
+  upfront.
+
+Some notes about using this template:
+
+* Your spec should be in ReSTructured text, like this template.
+
+* Please wrap text at 79 columns.
+
+* Please do not delete any of the sections in this template.  If you have
+  nothing to say for a whole section, just write: None
+
+* For help with syntax, see http://sphinx-doc.org/rest.html
+
+* If you would like to provide a diagram with your spec, ascii diagrams are
+  required.  http://asciiflow.com/ is a very nice tool to assist with making
+  ascii diagrams.  The reason for this is that the tool used to review specs is
+  based purely on plain text.  Plain text will allow review to proceed without
+  having to look at additional files which can not be viewed in gerrit.  It
+  will also allow inline feedback on the diagram itself.
+
+
+Problem description
+===================
+
+A detailed description of the problem. What problem is this blueprint
+addressing?
+
+Use Cases
+---------
+
+What use cases does this address? What impact on actors does this change have?
+Ensure you are clear about the actors in each use case: Developer, End User,
+etc.
+
+Proposed change
+===============
+
+Here is where you cover the change you propose to make in detail. How do you
+propose to solve this problem?
+
+If this is one part of a larger effort make it clear where this piece ends. In
+other words, what's the scope of this effort?
+
+At this point, if you would like to just get feedback on if the problem and
+proposed change fit in diskimage-builder, you can stop here and post this for
+review to get preliminary feedback. If so please say:
+Posting to get preliminary feedback on the scope of this spec.
+
+Alternatives
+------------
+
+What other ways could we do this thing? Why aren't we using those? This doesn't
+have to be a full literature review, but it should demonstrate that thought has
+been put into why the proposed solution is an appropriate one.
+
+API impact
+----------
+
+Describe how this will effect our public interfaces. Will this be adding new
+environment variables? Deprecating existing ones? Adding a new command line
+argument?
+
+Security impact
+---------------
+
+Describe any potential security impact on the system.
+
+Other end user impact
+---------------------
+
+Aside from the API, are there other ways a user will interact with this
+feature?
+
+Performance Impact
+------------------
+
+Describe any potential performance impact on the system, for example
+how often will new code be called, does it perform any intense processing
+or data manipulation.
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+Who is leading the writing of the code? Or is this a blueprint where you're
+throwing it out there to see who picks it up?
+
+If more than one person is working on the implementation, please designate the
+primary author and contact.
+
+Primary assignee:
+  <launchpad-id or None>
+
+Other contributors:
+  <launchpad-id or None>
+
+Work Items
+----------
+
+Work items or tasks -- break the feature up into the things that need to be
+done to implement it. Those parts might end up being done by different people,
+but we're mostly trying to understand the timeline for implementation.
+
+
+Dependencies
+============
+
+* Include specific references to specs in diskimage-builder or in other
+  projects, that this one either depends on or is related to.
+
+* If this requires functionality of another project that is not currently used
+  by diskimage-builder document that fact.
+
+
+Testing
+=======
+
+Please discuss the important scenarios needed to test here, as well as
+specific edge cases we should be ensuring work correctly. For each
+scenario please specify if this requires specialized hardware, or software.
+
+Is this untestable in gate given current limitations (specific hardware /
+software configurations available)? If so, are there mitigation plans (gate
+enhancements, etc).
+
+
+Documentation Impact
+====================
+
+Which audiences are affected most by this change, and which documentation
+files need to be changed. Do we need to add information about this change to
+the developer guide, the user guide, certain elements, etc.
+
+References
+==========
+
+Please add any useful references here. You are not required to have any
+reference. Moreover, this specification should still make sense when your
+references are unavailable. Examples of what you could include are:
+
+* Links to mailing list or IRC discussions
+
+* Links to notes from a summit session
+
+* Links to relevant research, if appropriate
+
+* Related specifications as appropriate
+
+* Anything else you feel it is worthwhile to refer to