Errors when the DSL calls an inflector method

[Samsinite]

Hi!
I keep getting:

undefined method `underscore' for "<resource singular name>":String

when a resource is saved.

I'd be happy to submit a PR to fix this, the gem already includes graphiti, which depends on active support, I believe that the DSL just needs to require 'active_support' and then require 'active_support/core_ext/string/inflections' in order to have access to these methods, but I could be mistaken. Adding that to the guard file at least is what worked for me.

[richmolj]

Thanks @Samsinite - I know we already do this in the main graphiti lib so this looks guard-specific. I'd love a PR to fix!