Configure Solve Media.

Important note: to deploy to Heroku, you need to assign each of the keys as environment variables by using `heroku config:set SOLVEMEDIA_CHALLENGE_KEY=<key>`, with <key> being the challenge key.
Create custom registrations controller to override default devise.
Add Solve Media to view. Add Solve Media error to Devise errors.
Add check for the rails test environment so the tests don't test the captcha.
Style captcha.
Add check if the rails environment is test or development.
Merge pull request #115 from nicolejpaz/add_captcha

Add Solve Media captcha
Merge pull request #11 from Ravenstine/master

Merge captcha