More roles flexibilty

Changed Roles multiselect in permission tab into separate checkboxes - now it's possible to create custom layouts with different permission-giving permissions.

Fixed user deletion bug

There was a bug that crashed user deletion, where there was no username in Object.
Kudos to @mischief24

Fixed user creation bug

v1.2.1

Fixed bug while creating User.

Mail sender

After account creation, an e-mail will be send with login link - this will allow password change.
Admin url config added - needed by e-mail funcionality.
Added button for updating Roles in BackendUser class.

First public release

v1.1.1

Added Readme.MD