Change wording on section Adding a Comment Model

[riseriyo]

Suggestion:
Change from:
"Let’s write a unicode_ method for our Comment model like we did for our Entry model earlier.

First we should create a test in blog/tests.py. Our test should look very similar to the unicode test we wrote for entries earlier. This should suffice:"

To:
"Before we write a unicode_ method for our Comment model similar to what we did for our Entry model earlier, let's first create a test in blog/tests.py.

Our test should look very similar to the unicode test we wrote for entries earlier. This should suffice:"