Make CONTRIBUTING.md slightly friendlier

Make CONTRIBUTING.md that little bit friendly by saying thanks at the top, and linking to issue reports new issue pages.

CONTRIBUTING.md

@@ -1,10 +1,13 @@
-## Filing issues
+Contributing to Draper
+===================
 
-To help us fix the problem you've found, please let us know your versions of Draper and Rails (and any other gems that are relevant to your issue, e.g. RSpec if you're having trouble in your tests).
+First of all, **thank you** for wanting to help and reading this!
+
+If you have found a problem with Draper, please [check to see](https://github.com/drapergem/draper/issues) if there's already an issue and if there's not, [create a new report](https://github.com/drapergem/draper/issues/new). Please include your versions of Draper and Rails (and any other gems that are relevant to your issue, e.g. RSpec if you're having trouble in your tests).
 
 ## Sending a pull request
 
-So you want to help us out... thanks! Here's a quick how-to:
+Thanks again! Here's a quick how-to:
 
 1. [Fork the project](https://help.github.com/articles/fork-a-repo).
 2. Create a branch - `git checkout -b adding_magic`
@@ -13,3 +16,5 @@ So you want to help us out... thanks! Here's a quick how-to:
 5. Commit your changes - `git commit -am "Added some magic"`
 6. Push the branch to Github - `git push origin adding_magic`
 7. Send us a [pull request](https://help.github.com/articles/using-pull-requests)!
+
+:heart: :sparkling_heart: :heart: