Red:  ModelDecorator#uuid adds a Version 5 (SHA-1 hash) UUID

-----FAILING TEST-----

1) ModelDecorator#uuid adds a Version 5 (SHA-1 hash) UUID
   Failure/Error: @model = model.new
   NoMethodError:
     undefined method `new' for nil:NilClass
Add uuidtools gem
Add UUID column to SignUp model
Add pry-rails gem