Help me bout gem 'acts_as_api' in RoR

I’m working with ‘acts_as_api’ but I cant’t understand how it to do
I try to find tutorial about it with a small project using gem
‘acts_as_api’
but I’m afraid it is none.
who can give me some advice to build small project use gem ‘acts_as_api’
Thanks…

I have done this small demo with :
https://github.com/fabrik42/acts_as_api/blob/master/examples/introduction/index.rb
and scaffold in Rails