Remove superflous columns from the users table

db/migrate/20160225050318_allow_defaults_on_users_table.rb

@@ -0,0 +1,10 @@
+class AllowDefaultsOnUsersTable < ActiveRecord::Migration
+  def up
+    # we need to temporarily change table a bit to ensure we can insert new records
+    change_column :users, :email_digests, :boolean, null: false, default: true
+    change_column :users, :external_links_in_new_tab, :boolean, null: false, default: false
+  end
+
+  def down
+  end
+end