Now that we have database in place we need to add another validations to sign up process. We must ensure that email and username are unique, because both of these fields will serve as user identifiers.

Links:

- Repository: https://github.com/Remchi/reddice
- Blog Post: http://remzolotykh.net/react-and-redux-13-user-sign-up-uniqueness-validation/
- Follow me on twitter: https://twitter.com/remzolotykh