User.SignUpAsync() doesn't signup

As stated in the issue #77 if I need to create new user with just Username/email and password I am not able to create it, and I cannot see the user in database.

MoralisUser user = new MoralisUser();
user.username = "email";
user.email = "email";
user.password = "password";
await user.SignUpAsync();

[Denchyaknow]

Just wanted to note that Signup also does not currently set current User as described in #95.

Current: Signup is called and return User object from DB, DB shows same User. But GetUserAsync() is null as well as other GetUser()/GetClient().GetCurrentUser() methods.

Expected: Signup is called and MoralisInterface.GetUserAsync() can be called right after or later on to get the same user.

Excited for next release 😄

[xactant]

Internal Backlog item #69 created for this issue.