Fix all the errors to get our tests green on Rails 5.1.

db/migrate/20121129184948_remove_email_token_from_users.rb

@@ -1,4 +1,4 @@
-class RemoveEmailTokenFromUsers < ActiveRecord::Migration
+class RemoveEmailTokenFromUsers < ActiveRecord::Migration[4.2]
   def up
     execute "INSERT INTO email_tokens (user_id, email, token, created_at, updated_at)
               SELECT id, email, email_token, CURRENT_TIMESTAMP, CURRENT_TIMESTAMP