Started working on User management
Finished user management

Now possible to add / delete users.
Add a user: crowd-summary.dev/users/add
Login: crowd-summary.dev/users/login
Logout: crowd-summary.dev/users/logout
Users overview (only when logged in): crowd-summary.dev/users
Removed info.php
Merge pull request #2 from yetti4/user-management

User management