Change the git_branches table primary key

To allow for having branches in multiple git repositories.

sqitch/deploy/change_git_branches_primary_key.sql

@@ -0,0 +1,9 @@
+-- Deploy guix-data-service:change_git_branches_primary_key to pg
+
+BEGIN;
+
+ALTER TABLE git_branches DROP CONSTRAINT name_commit;
+
+ALTER TABLE git_branches ADD PRIMARY KEY (name, commit, git_repository_id);
+
+COMMIT;

sqitch/revert/change_git_branches_primary_key.sql

@@ -0,0 +1,9 @@
+-- Revert guix-data-service:change_git_branches_primary_key from pg
+
+BEGIN;
+
+ALTER TABLE git_branches DROP CONSTRAINT git_branches_pkey;
+
+ALTER TABLE git_branches ADD PRIMARY KEY (name, commit);
+
+COMMIT;

sqitch/sqitch.plan

@@ -16,3 +16,4 @@ load_new_guix_revision_job_events 2019-06-02T15:44:41Z Christopher Baines <mail@
 load_new_guix_revision_job_logs 2019-06-21T14:33:09Z chris <chris@phact> # Add load_new_guix_revision_job_logs
 change_load_new_guix_revision_job_logs_contents_to_be_nullable 2019-07-07T20:10:54Z Christopher Baines <mail@cbaines.net> # Change the contents field in the load_new_guix_revision_job_logs table\nto be nullable.\n\nwith '#' will # be ignored, and an empty message aborts the add.  #\nChange to add: # #\nchange_load_new_guix_revision_job_logs_contents_to_be_nullable #\nsqitch/deploy/change_load_new_guix_revision_job_logs_contents_to_be_nullable.sql\nsqitch/revert/change_load_new_guix_revision_job_logs_contents_to_be_nullable.sql\nsqitch/verify/change_load_new_guix_revision_job_logs_contents_to_be_nullable.sql
 fix_duplicated_licenses 2019-07-30T05:48:17Z Christopher Baines <mail@cbaines.net> # Fix duplicated licenses, and add constraints
+change_git_branches_primary_key 2019-08-05T18:57:41Z Christopher Baines <mail@cbaines.net> # Change the git_branches primary key to include the git_repository_id,\nas this will allow having the same branch in different repositories.

sqitch/verify/change_git_branches_primary_key.sql

@@ -0,0 +1,7 @@
+-- Verify guix-data-service:change_git_branches_primary_key on pg
+
+BEGIN;
+
+-- XXX Add verifications here.
+
+ROLLBACK;