Replace 'girl' with 'bot' everywhere

Also: add a deprecation warning to factory_girl, asking users to switch to
factory_bot

#921

CONTRIBUTING.md

@@ -1,4 +1,4 @@
-# Contributing to Factory Girl
+# Contributing to Factory Bot
 
 We love pull requests from everyone. By participating in this project, you
 agree to abide by the thoughtbot [code of conduct].
@@ -17,7 +17,7 @@ Here are some ways *you* can contribute:
 * by closing [issues][]
 * by reviewing patches
 
-[issues]: https://github.com/thoughtbot/factory_girl/issues
+[issues]: https://github.com/thoughtbot/factory_bot/issues
 
 ## Submitting an Issue
 
@@ -52,7 +52,7 @@ already been submitted.
   asking for help. We love helping!
 * Please don't update the Gem version.
 
-[repo]: https://github.com/thoughtbot/factory_girl/tree/master
+[repo]: https://github.com/thoughtbot/factory_bot/tree/master
 [fork]: https://help.github.com/articles/fork-a-repo/
 [branch]: https://help.github.com/articles/creating-and-deleting-branches-within-your-repository/
 [pr]: https://help.github.com/articles/using-pull-requests/