Generate User model and test stubs.
Install Annotate. Annotate the User model and spec.
Test that User fields :name and :email exist.
Write test for presence of user :name and :email, and then implement it.
Test and implement User :name maximum length is 50 characters.
Test and implement User :email is a validemail address.
Test that a user's email is unique.  Implement it.
Install bcrypt for encrypting User passwords.
Write tests that validate the presence and elength of User :password and :password_confirmation.  Implement the code.