The find_or_initialize and find_or_create methods have been deprecated in Rails x.x.x. This is what you need to do:

Before:
User.find_or_create_by_name('XXX')

After:
User.find_or_create_by(name: 'XXX')

Before:
User.find_or_initialize_by_name('XXX')

After:
User.where(name: 'XXX').first_or_initialize

If you want the old methods, see https://github.com/rails/activerecord-deprecated_finders.

Also see http://apidock.com/rails/ActiveRecord/Relation/first_or_create