Function: Generate custom avatar for dozent resources

Function: Get the user object in database format by User ID

Function: Get the user by field or from the query_var, from Dozent User page

Function: Return all activity records related an user for the Dozent LMS

Function: Get the user profile photo ID

Function: Add an instructor to a course

Function: Detach / delete an instructor from the course instructors list.

Function: Check if an instructor attached with a course

Function: Get all instructor attached in a course

Function: Get the all instructor ID in an array by a specific course