Code review comment for lp:~rockstar/launchpad/merge-queues-db

You are missing comments in comments.sql for the new Branch
columns (merge_queue and merge_queue_config).

Needs a few indexes:

CREATE INDEX branchmergequeue__registrant__idx
ON BranchMergeQueue(registrant);

CREATE INDEX branch__merge_queue__idx ON Branch(merge_queue);

As BranchMergeQueue.name might end up appearing in URLs, we should ensure
it is sane:

ALTER TABLE BranchMergeQueue
    ADD CONSTRAINT valid_name CHECK (valid_name(name));

The statement to schedule the BranchMergeRobot table to be dropped is
incorrect. We need the following:

    ALTER TABLE BranchMergeRobot SET SCHEMA todrop;

patch-2208-22-0.sql