Branch py3-venv3 Initial commit: add .gitignore file

After I checkout this git repository, first of all, I don't want to use
Django 1.5, because when I start to learn Django, the current release is
Django 1.6.4. And also, I don't want to use python 2 (or python 2.7, to
be more precise), because I think Python 3 is really cool.

So problems arise when switching dependency versions. I use python3 and
virtualenv3 with virtualenvwrapper, and as for Django, it's 1.6.4. This
branch aims to correct all the errors caused by using this new
environment. At last, it ensures all the tests written in master branch
run and pass, and provides more information about this django test demo
project.
Add README.md file under py3-venv3 directory
Correct error in django15/whatever/form.py

It's a import statement error.
Correct the import error in django15/django15/url.py
Corrent error in django15/whatever/tests.py

The `HttpResponse` object has a `content` attribute which contains "a
string representation of the content encoded from a Unicode object if
necessary" (from Django Doc 1.6). So it's essential to decode the bytes
string before using `assertIn`. This is a common pitfall when using
Python 3.
Correct error in django15/whatevs/models.py

Since we use Python 3 here, `unicode` should be `str`.
Add requirements.txt file
Modify branch README.md file

Add explanation about package dependency.
Add Changed test.db file
Make changes for my package environment

Merge branch 'py3-venv3'

* py3-venv3:
  Add Changed test.db file
  Modify branch README.md file
  Add requirements.txt file
  Correct error in django15/whatevs/models.py
  Corrent error in django15/whatever/tests.py
  Correct the import error in django15/django15/url.py
  Correct error in django15/whatever/form.py
  Add README.md file under py3-venv3 directory
  Branch py3-venv3 Initial commit: add .gitignore file