Added support of underscored arguments in have_field

[makketagg]

The simple solution for underscored arguments in the have_field matcher. Fixed #28

[makketagg]

Hey @khamusa. Can we update the bundler version? On local machine works great, but the TravisCI doesn't work

[khamusa]

Thanks for the PR, LGTM. I see from the commits history you tried solving the bundler issue yourself. No problem, we can update the bundler version. Let me know if you need me to do anything else.

[makketagg]

@khamusa thanks for response. Probably, I found solution for ci - https://docs.travis-ci.com/user/languages/ruby/

If you are using Ruby 2.3.x but wish to explicitly stay on Bundler 1.x (e.g., for dependency reasons such as Rails 4.2.x), write:

before_install:
  - gem uninstall -v '>= 2' -i $(rvm gemdir)@global -ax bundler || true
  - gem install bundler -v '< 2'

Let's try

UPD
Doesn't work

Gem bundler-2.1.2 cannot be uninstalled because it is a default gem

Upgraded bundler version