Added new field for User - a name. 

* Added new field for user - a name. 
* Refactored registering so the user has to input the name (beginning with a capital letter). 
* Moved the initials of the author to user. Also added a method called author to Question so we don't have to change all the views which display author (I'm displaying user.name as author now). 
* Edited forms so the Author cannot be input now. And most of all refactored tests (added test for User which now checks most of validations on author which was tested in Question before).
Sorry for the delay, I've had a busy week :) I'll now continue the CR now and let you know when it's finished. Then you can make new commits (with corrections) and push the changes. They should appear here automatically.

For future PRs, you should create separate (and independent) branches for separate features (eg. `user-name-field` branch with new user field and tests for it), and create Pull Request from this branch. This way, it's easier for me to make the CR (as there is less code to review at once), and easier for you to fix things in individual branches that refer to single features).