Added Session 07 Homework

Here's my session 07 homework.  Please review and provide your feedback.

- Salim
Not quite what I was looking for. In this case, you would need to  pass the tag into the decorated function. I was thinking that yo would pass the tag into the decorator itself -- the function being decorated doesn't need to know anythign about tags.

@add_tag(tag='div')
def some_func_that_returns_a_string():
    ....