Implement editing profile, including uploading profile image

* Added gems 'carrierwave' and 'mini_magick'
* `rails g uploader ProfileImage` generated the uploader directory and
* uploader file
* Migration for adding column profile_image to User
* Added carrierwave.en.yml to incorporate flash messages
* Implemented tests for editing profile including uploading a profile
* image
* Implemented spec for profile_image_uploader to ensure it works
* properly