The db.api module provides a useless indirection to the only
implementation we ever had, sqlalchemy. Let's use that directly instead
of the wrapper.
Change-Id: I80353cfed801b95571523515fd3228eae45c96ae
Retrieving the field from the db object triggers the query to
stack_tags, so we don't need to do it a second time to retrieve the list
of tags. Instead, use the data directly.
Change-Id: Ibe6ac45d54afca6588b1b71ffa7278977d2f4d8a
Adds support for versioning object support for StackTag
and add it to the Stack object
Closes-bug: #1432477
Implements blueprint versioned-object
Change-Id: I7cc39c1e1ce913c35862a52592e55b9f484c7e68
Thomas Herve