Trove/associate-flavors-datastores

=Overview= This proposal includes the ability to associate flavor types with datastore versions. The trove-manage utility will provide the ability to add/delete this information. An example use case of this feature is say we have an enterprise version datastore which requires minimum 2GB flavor associated with it. There is no way to currently to enforce that.

= API Resources =

Summary
Existing Routes (that will remain untouched)

New Routes

List Flavors (GET)
This call lists all flavors for a given datastore version

/{tenant_id}/flavors/datastores/versions/{datastore_version_id}

Response

{ "flavors": [ {       "id": 1, "links": [ {                      "href": "https://ord.databases.api.rackspacecloud.com/v1.0/1234/flavors/1", "rel": "self" },                     {                       "href": "https://ord.databases.api.rackspacecloud.com/flavors/1", "rel": "bookmark" }                  ],        "name": "512MB Instance", "ram": 512 }, ] }

Trove-manage util extension
trove-manage datastore-version-flavor-add datastore_version_id flavor_id_list trove-manage datastore-version-flavor-delete datastore_version_id flavor_id

=Database Schema= One new entity will be created in the trove database: datastore_version_metadata. This will store any additional metadata related to a datastore version including its relation with flavors - key=flavor and the value=flavor_id.

Datastore Version Metadata 

This table will contain the id, datastore_version_id, key and value

Other Comments
There is an older blueprint https://blueprints.launchpad.net/trove/+spec/service-type-filter-on-flavors which got abandoned. I propose that it should be broken up into to blueprints : This spec elaborates on (2) and can be used for the same.
 * 1)  Ability to add flavors via trove
 * 2) Associating flavors with datastore versions