Improve db

#8 @gsathya @ben-jones 
I changed directory structure and split server.py into models and views.
This is correct. See the example below and https://docs.python.org/2/library/stdtypes.html#mapping-types-dict

Python 2.7.6 (default, Mar 22 2014, 22:59:38) 
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> stuff = {'a': 4}
>>> stuff['a']
4
>>> stuff['b']
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyError: 'b'
>>> stuff.get('b')
>>> print stuff.get('b')
None