Expect relays to answer with accept/reject (#8179)

db/migrate/20180812123222_change_relays_enabled.rb

@@ -0,0 +1,19 @@
+class ChangeRelaysEnabled < ActiveRecord::Migration[5.2]
+  def up
+    # The relays table is supposed to be very small,
+    # single-digit number of rows, so this should be fine
+    safety_assured do
+      add_column :relays, :state, :integer, default: 0, null: false
+
+      # At the time of this migration, no relays reject anyone, so if
+      # there are enabled ones, they are accepted
+      execute 'UPDATE relays SET state = 2 WHERE enabled = true'
+      remove_column :relays, :enabled
+    end
+  end
+
+  def down
+    remove_column :relays, :state
+    add_column :relays, :enabled, :boolean, default: false, null: false
+  end
+end