Merge pull request 'Removed manual check of email' (#35) from manual-email-check into develop

Reviewed-on: #35

src/main/java/se/su/dsv/seshat/services/UserService.java

@@ -17,9 +17,6 @@ public class UserService {
         if (appUserRepository.existsByUsername(username)) {
             throw new IllegalArgumentException("Username already exists");
         }
-        if (appUserRepository.existsByEmail(email)) {
-            throw new IllegalArgumentException("Email already exists");
-        }
 
         AppUser newUser = new AppUser(username, email, "USER");
         appUserRepository.save(newUser);