ActiveRecord::Result#to_hash doesn't return a hash

That method seems to be private API of Rails (at least it should be) so go ahead to remove/deprecate it.

Ok, cool. I’ve never done this before, so I just wanted to make sure I’m doing this as expected by the community.

I’ve cloned the repo and gotten all the tests that already pass, passing. I repeated the same after my proposed change, and I’ll submit a pull request once I’ve got everything organized.

Let me know if I should do anything differently.