login issue.

[jjhesk]

@aitoraznar did you get the login issue resolved?

Unhandled error for request POST /users/login?include=user: Error: username or email is required

as found from the login

[aitoraznar]

I don't remember right now.

I forked this repo and switch the code into VanillaJS.
https://github.com/aitoraznar/loopback-component-admin/

However, this admin isn't very usable for me.