Update CONTRIBUTING.md

Author: Eonasdan

CONTRIBUTING.md

@@ -1,12 +1,6 @@
 Contributions guidelines:
 
 - Use 2 spaces indentation
-- If it is a bug, try to add an automated test that reproduces it in the
-  test/issues.coffee, following the conventions already adopted.
-- If it is a new feature, try to add automated tests for it.
-- Never submit patches that break existing tests(make test should take care of
-  downloading dependencies and running the tests)
-- Do not commit the files in the 'build' dir, 'git update-index --assume-unchanged build/{js,css}/*' will help
-
-Before starting to develop, enter 'make deps' to download all dependencies
-needed for developing/testing. 'make test' will run all tests. 
+- If it is a bug, please read open issues to avoid duplicates
+- If it is a new feature, please provide a use case. E.g. Why this feature should be added and what you are using it for
+- If possible, please provide example code and/or a jdfiddle and a DETAILED example of what is not working