Form validation is not finished, and will not be finished (by me) because
today is probably last day of my technical internship. What I have managed
to do in this commit & push:
1. I have added error alert on "Bad credentials" in on login in login.html
2. I have edited bug i User class, and all code that had to be edited
after class editing. What was the error? Instead of currentPassword property
there was curentPassword property. A lot of code in front-end uses current*
keyword, cod was working but it was bad programming practice.

Signed-off-by: Ljubomir Papuga <papuga.yu@gmail.com>