Add blog app with simple view, necessary settings, url-patterns

[tobias47n9e]

This is the first skeleton of the blog app. From the url-root
all patterns starting with '/blog/' will be redirected to
the blog. As of now the blog only has one simple view that
sends a text as HttpResponse. The reachability of the page
and the unreachability of the subpages is tested. The folder
contriblog is now part of the INSTALLED_APPS.

Part of: #45

[coolharsh55]

IMHO, this seems redundant. Asserting that invalid views return 404 is not necessary, otherwise we'd need to assert that EVERY app url that isn't valid returns a 404. Also, creating the url through string concatenation beats the purpose of using reverse.

response = client.get(reverse("blog:index") + "december")

We could proceed with development on the blog branch, and only merge with master when certain features are finished and stable. For blog, it could be creating the blog models, templates, and making it functional, and integrating it in to master as a single commit.

[SanketDG]

@coolharsh55 I believe @tobias47n9e just had to write some tests for the sake of TDD. Otherwise, no sane developer can check for 200 and 404 status assertions for every app url.

As soon as we get some code, we could write some real tests and remove these redundant, trivial ones. Otherwise, this is ready to go in.