Added failing test for unique email validation
Unique email validation added to User.register() and passes all tests
(50/50)
Refactored Neo4j queries into neo() function, reducing code duplication
and bringing Coverage to 100%
Added failing test for invalid email format
Email format is now validated and passing all tests. Additionally moved
lowercasing of email address into UserModel
Merge pull request #4 from asifrc/user-register

User register