A User Collection extends a Collection, adding the functionality needed to authenticate users with your app. You can create one by choosing "User Collection" when adding a Resource.
User Collections can have the same properties as a Collection, with two additional non-removable properties:
username - The user's identifier; must be unique.
password - An encrypted password. It can never be retrieved from the database, only queried against.
In addition to the above constraints, these two properties can only be modified by: