migrations: add packages.documentation column

Change-Id: Iecf325408aef16c87d853500299d3fcc5c58d673
Reviewed-on: https://team-review.git.corp.google.com/c/golang/discovery/+/456997
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

migrations/000036_add_packages_documentation_column.down.sql

@@ -0,0 +1,9 @@
+-- Copyright 2019 The Go Authors. All rights reserved.
+-- Use of this source code is governed by a BSD-style
+-- license that can be found in the LICENSE file.
+
+BEGIN;
+
+ALTER TABLE packages DROP COLUMN documentation;
+
+END;

migrations/000036_add_packages_documentation_column.up.sql

@@ -0,0 +1,9 @@
+-- Copyright 2019 The Go Authors. All rights reserved.
+-- Use of this source code is governed by a BSD-style
+-- license that can be found in the LICENSE file.
+
+BEGIN;
+
+ALTER TABLE packages ADD COLUMN documentation TEXT;
+
+END;