Update copy on CONTRIBUTING.md, write in active voice

CONTRIBUTING.md

@@ -1,16 +1,16 @@
 How you can help
 ================
 
-1. Documentation (website copy, code comments, typos, etc)
-2. Fixing [bugs](https://github.com/nusmodifications/nusmods/issues)
-3. Writing unit tests
-4. Refactoring code
+1. Write documentation (website copy, code comments, typos, etc)
+2. Fix [bugs](https://github.com/nusmodifications/nusmods/issues)
+3. Write tests
+4. Refactor code
 
 Steps to contribute
 -------------------
 1. Fork this project
-2. Report bug by [creating an issue](https://github.com/nusmodifications/nusmods/issues/new)
-3. Fix the bug and run tests
+2. Report a bug or suggest a feature by [creating an issue](https://github.com/nusmodifications/nusmods/issues/new)
+3. Fix the bug or implement the feature and show us how to test it! (we don't have tests right now, this is a TODO, pull requests welcome :P)
 4. Commit the fix to your branch and make a pull request
 
 Newcomers can look for issues with the [good for newcomers](https://github.com/nusmodifications/nusmods/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+for+newcomers%22)