FEATURE: Support an end date for user silencing

db/migrate/20171113175414_add_silenced_till_to_users.rb

@@ -0,0 +1,14 @@
+class AddSilencedTillToUsers < ActiveRecord::Migration[5.1]
+  def up
+    add_column :users, :silenced_till, :timestamp, null: true
+    execute <<~SQL
+      UPDATE users
+        SET silenced_till = CURRENT_TIMESTAMP + INTERVAL '1000 YEAR'
+        WHERE silenced
+    SQL
+  end
+
+  def down
+    add_column :users, :silenced_till
+  end
+end