Add google authentication
:nail_care:
Explain to user that twitter sign in is only for existent users.
:scissors: non necessary spec.
Refactor: simplify (dries) the auxiliar sign_in_via_* methods.
Add logic to forbidden account creation via twitter.
Refactoring: swipe under the carpet the decision making for create authentications or not.
Refactor: :scissor: Reduce the conditionals and bumps to aggregate authentications for signed_in users.
Refactor: moving responsabilities to the right place.
:scissors:
[ wip ] - pushing more responses into `Authentication`
Greenify the specs
Refactor: a nice way to access user auth info
Remove code that doesn’t make sense now that all users will have email.
:nail_care:
Refactor: `bumba meu boi` of methods. :sob:
:nail_care:
Add class stolen from branch: user-merge-tool
Add the feature for users to merge their other auth providers with the current profile.
Add profile spec as is from branch `user-merge-tool`