Allow Extend on users

This was one that was bugging me a little since I wanted to add profile pics and maybe some social links etc.

![http://cl.ly/image/3Z0J3a03430D/Image%202014-10-09%20at%2010.27.11%20AM.png](http://cl.ly/image/3Z0J3a03430D/Image%202014-10-09%20at%2010.27.11%20AM.png)

![http://cl.ly/image/2D23430L3H0e/Image%202014-10-09%20at%2010.27.52%20AM.png](http://cl.ly/image/2D23430L3H0e/Image%202014-10-09%20at%2010.27.52%20AM.png)

This addition makes the custom fields appear above the user login info. This page may need a layout update now that fields can be added.

Please test and let me know if anything dies.