Teachers can now upload a file for an assignment. The file can be downloaded from the assignment page. File can be deleted. Using .zip you multiple files can be uploaded.
Screenshots
Can upload file:
Can download file:
Can delete uploaded file (shown iff there is an uploaded file)
What changes have you made (detailed)?
Can upload file (can upload multiple with .zip file) in add assignment and edit assignment.
Can delete uploaded file in edit assignment (if it has been uploaded).
Button to download assignment file in assignment page (visible to everyone in the assignment and only if there exists an uploaded file).
Write tests
Does this MR meet the acceptance criteria?
The main application was run to make sure the server still runs without errors.
Tests were written to verify the behaviour of this code.
Javadoc and other comments were added to make the code understandable.
