Add Docker support [WIP]

Allow development of `lutris/website` through [Docker](https://www.docker.com/), so that you don't need to install any other dependencies locally. Still running into errors on install, however. Do you guys know what it's missing?

``` bash
$ sudo docker run -p 8000:80 -v $(pwd):/app lutris/website start
pip install -r config/requirements/devel.pip --exists-action=s
Requirement already satisfied (use --upgrade to upgrade): setuptools>=1.1.0 in /usr/local/lib/python3.4/site-packages (from -r config/requirements/base.pip (line 1))
Downloading/unpacking PyYAML (from -r config/requirements/base.pip (line 2))
  Running setup.py (path:/tmp/pip_build_root/PyYAML/setup.py) egg_info for package PyYAML
    
Downloading/unpacking Django==1.6.6 (from -r config/requirements/base.pip (line 3))
Downloading/unpacking Pillow==2.4.0 (from -r config/requirements/base.pip (line 4))
  Running setup.py (path:/tmp/pip_build_root/Pillow/setup.py) egg_info for package Pillow
    
Downloading/unpacking South>=0.8.4 (from -r config/requirements/base.pip (line 5))
  Running setup.py (path:/tmp/pip_build_root/South/setup.py) egg_info for package South
    
Downloading/unpacking ipython>=1.1.0 (from -r config/requirements/base.pip (line 6))
Downloading/unpacking nose (from -r config/requirements/base.pip (line 7))
  Running setup.py (path:/tmp/pip_build_root/nose/setup.py) egg_info for package nose
    
    no previously-included directories found matching 'doc/.build'
Downloading/unpacking Sphinx>=1.2b3 (from -r config/requirements/base.pip (line 8))
Downloading/unpacking django-compressor>=1.2 (from -r config/requirements/base.pip (line 9))
Downloading/unpacking django-crispy-forms>=1.4.0 (from -r config/requirements/base.pip (line 10))
  Running setup.py (path:/tmp/pip_build_root/django-crispy-forms/setup.py) egg_info for package django-crispy-forms
    
    warning: no files found matching '*' under directory 'crispy_forms/static'
Downloading/unpacking django-select2==4.2.2 (from -r config/requirements/base.pip (line 11))
  Running setup.py (path:/tmp/pip_build_root/django-select2/setup.py) egg_info for package django-select2
    Traceback (most recent call last):
      File "<string>", line 17, in <module>
      File "/tmp/pip_build_root/django-select2/setup.py", line 154
        print data['error_code']
                 ^
    SyntaxError: Missing parentheses in call to 'print'
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):

  File "<string>", line 17, in <module>

  File "/tmp/pip_build_root/django-select2/setup.py", line 154

    print data['error_code']

             ^

SyntaxError: Missing parentheses in call to 'print'
```