Create Ops Strategies User Lists Table

What does this MR do?

Create operations_strategies_user_lists table.

This is for associating a feature flag strategy with a user list so that a feature flag can be enabled for a reusable list of users. See the issue for more details about the feature.

Issue: #35930 (closed)

Migration Output

$ bin/rails db:migrate
== 20200422213749 CreateOperationsStrategiesUserLists: migrating ==============
-- create_table(:operations_strategies_user_lists)
   -> 0.0088s
== 20200422213749 CreateOperationsStrategiesUserLists: migrated (0.0089s) =====

$ bin/rails dbconsole
psql (10.12)
Type "help" for help.

gitlabhq_development=# \d operations_strategies_user_lists
                               Table "public.operations_strategies_user_lists"
    Column    |  Type  | Collation | Nullable |                           Default                            
--------------+--------+-----------+----------+--------------------------------------------------------------
 id           | bigint |           | not null | nextval('operations_strategies_user_lists_id_seq'::regclass)
 strategy_id  | bigint |           | not null | 
 user_list_id | bigint |           | not null | 
Indexes:
    "operations_strategies_user_lists_pkey" PRIMARY KEY, btree (id)
    "index_ops_strategies_user_lists_on_strategy_id_and_user_list_id" UNIQUE, btree (strategy_id, user_list_id)
    "index_operations_strategies_user_lists_on_user_list_id" btree (user_list_id)
Foreign-key constraints:
    "fk_rails_43241e8d29" FOREIGN KEY (strategy_id) REFERENCES operations_strategies(id) ON DELETE CASCADE
    "fk_rails_ccb7e4bc0b" FOREIGN KEY (user_list_id) REFERENCES operations_user_lists(id) ON DELETE CASCADE

gitlabhq_development=# \q
$ bin/rails db:rollback
== 20200422213749 CreateOperationsStrategiesUserLists: reverting ==============
-- drop_table(:operations_strategies_user_lists)
   -> 0.0014s
== 20200422213749 CreateOperationsStrategiesUserLists: reverted (0.0024s) =====

$ bin/rails dbconsole
psql (10.12)
Type "help" for help.

gitlabhq_development=# \d operations_strategies_user_lists
Did not find any relation named "operations_strategies_user_lists".
gitlabhq_development=# \q
$ 

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

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• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team