Add ADL versioning proposal

Change-Id: I1583bf33eda6685f54fc1ed520fe4f6767e3345b

specs/adl_versioning_spec.rst

@@ -0,0 +1,85 @@
+=====================================================
+Application Definition Language (ADL) Versioning Tool
+=====================================================
+
+The goal of this spec is creating versioning mechanism for ADL
+
+
+Problem description
+===================
+
+The problem is that our ADL may be changed. Some modifications are
+backward compatible, some of them are not. And we may have situation when
+service file written for old ADL version will be deployed using new fuel-ccp
+tool which is not support that old version of ADL.
+
+Use Cases
+---------
+
+#. User try to deploy services with newer version then fuel-ccp ADL version,
+   services files are incompatible with fuel-ccp tool.
+#. User try to deploy services with older or equal version then fuel-ccp ADL
+   version, services files are compatible with fuel-ccp tool
+#. User try to deploy services with older version then fuel-ccp ADL
+   version, services files are incompatible with fuel-ccp tool
+
+Proposed change
+===============
+
+#. Introduce two part ADL versioning in fuel-ccp tool. If major version is
+   changed this means that change is not backward compatible
+#. Keep ADL version for each services repository to store version of ADL used
+   for writing services of current repository.
+#  Check version compatibility during "fuel-ccp deploy" call according next
+   rules:
+   #. if fuel-ccp's ADL version is less then service's ADL version -
+      they are incompatible
+   #. if major part of these versions are different - they are incompatible
+   #. otherwise they are compatible and deploy should be continued.
+
+
+Alternatives
+------------
+
+Leave as is of invent some another versioning approach
+
+Implementation
+==============
+#. Add versions to all service's repos
+#. Add version to fuel-ccp repo
+#. Add logic to fuel-ccp deploy for handling vesion validation
+
+Assignee(s)
+-----------
+dukhlov
+
+Work Items
+----------
+#. implement patch for fuel-ccp
+#. implement patches for service's repos
+
+Dependencies
+============
+None
+
+
+Testing
+=======
+
+Unit testing for fuel-ccp version validation logic
+
+
+Documentation Impact
+====================
+
+Describe version bump rules
+
+References
+==========
+
+None
+
+History
+=======
+
+None