Merge pull request #1 from menghong777/master

Added sign in and sign up
Sign up page to social platform login
Add Auth0 authentication

Please refer to http://www.auth0.com
We are using the domain http://animalrescue.auth0.com
Integration with: Facebook, Google+, Twitter
Auth0 will handle all backend authentication
Merge branch 'master' of github.com:hanxue/AnimalRescue