In my project ELP I decided to start with core implementation of backend side. I started with service for sign in and register user accounts. I use TDD approach, so I create test with expected result that fails at the beginning and then I implement code to pass this test. I created MembershipService in my project that is responsible for creating accounts, validating, etc. This service uses other services like UserService for getting users from database or UserRoleService for getting user r...