scaffoled disease controller

@FatmaEmran @tonyfoti @mohamed-halawa @sedramina 
please review the code, I have simply scaffoled the Disease model with the command:-
"rails g scaffold_controller Disease"
@mostafa-adel @kalamoni 
Since I am the Doc Reviewer of my own team, I cannot reiview myself.
if you can take a moment of your time to review the documentation it will be greatly appreciated.
 Thanks in advance.