Cannot load such file -- pay_u/response

I have this code, it works locally but on Travis it does not.

...
require 'pay_u/errors'
require 'pay_u/response'
require 'pay_u/requests/authorize'
...

I am getting the error

An error occurred while loading spec_helper.
Hint: Install the `did_you_mean` gem in order to provide suggestions for similarly named files.
Failure/Error: require 'pay_u/response'
LoadError:
  cannot load such file -- pay_u/response
# ./lib/pay_u.rb:11:in `require'
# ./lib/pay_u.rb:11:in `<top (required)>'
# ./spec/spec_helper.rb:2:in `require'
# ./spec/spec_helper.rb:2:in `<top (required)>'
No examples found.
No examples found.
Finished in 0.00003 seconds (files took 0.08183 seconds to load)
0 examples, 0 failures, 1 error occurred outside of examples
Finished in 0.00003 seconds (files took 0.08183 seconds to load)
0 examples, 0 failures, 1 error occurred outside of examples

It works fine locally. Why am I getting this error?

https://travis-ci.org/jedrekdomanski/pay_u

The error message – cannot load such file -- pay_u/response – is pretty informative.

If something works locally but not in Travis, this means there are differences between your local machine and Travis environment: uncommitted changes, globally installed gems etc.

Oh my God, you know what? Or maybe I am not saying anything to avoid shame. I … forgot to add this file to repository…I can’t believe I did that. So sorry, my bad.