Merge lp:~cjwatson/launchpad/db-bzr-webhooks into lp:launchpad/db-devel

[Colin Watson]

Add Webhook.branch.

Add Webhook.branch. It's relatively easy to get Bazaar branch webhooks working given this.

[William Grant (wgrant)]

review: Approve (db)

=== added file 'database/schema/patch-2209-66-1.sql'
--- database/schema/patch-2209-66-1.sql	1970-01-01 00:00:00 +0000
+++ database/schema/patch-2209-66-1.sql	2015-09-24 12:10:24 +0000
@@ -0,0 +1,14 @@
+-- Copyright 2015 Canonical Ltd.  This software is licensed under the
+-- GNU Affero General Public License version 3 (see the file LICENSE).
+
+SET client_min_messages=ERROR;
+
+ALTER TABLE Webhook ADD COLUMN branch integer REFERENCES Branch;
+
+ALTER TABLE Webhook DROP CONSTRAINT webhook_git_repository_check;
+ALTER TABLE Webhook ADD CONSTRAINT one_target CHECK ((git_repository IS NOT NULL) != (branch IS NOT NULL));
+
+CREATE INDEX webhook__branch__id__idx
+    ON webhook(branch, id) WHERE branch IS NOT NULL;
+
+INSERT INTO LaunchpadDatabaseRevision VALUES (2209, 66, 1);