Fixed typo in docs/intro/contributing.txt.

docs/intro/contributing.txt

@@ -230,7 +230,8 @@ some other flavor of Unix, run:
     $ ./runtests.py
 
 Now sit back and relax. Django's entire test suite has thousands of tests, and
-it takes at least a few minutes run, depending on the speed of your computer.
+it takes at least a few minutes to run, depending on the speed of your
+computer.
 
 While Django's test suite is running, you'll see a stream of characters
 representing the status of each test as it completes. ``E`` indicates that an