add stats view group (bug 897528)

migrations/632-stats-viewer-group.sql

@@ -0,0 +1,4 @@
+INSERT INTO groups (name, rules, created, modified, notes)
+        VALUES ('Statistics Viewers', 'Stats:View', NOW(), NOW(), 'To view consumer statistic pages and access statistics API.');
+
+UPDATE `groups` SET rules=CONCAT(rules, ',Stats:View') WHERE name='Staff';