README: Add a section explaining how to report bugs

Suggested-by: Petr Bena <benapetr@gmail.com>

README.rst

@@ -75,6 +75,22 @@ For instructions how to do this, see documentation on `Running CMake`_.
 
 .. _`Running CMake`: http://www.cmake.org/cmake/help/runningcmake.html
 
+Reporting Bugs
+==============
+
+If you have found a bug:
+
+1. If you have a patch, please read the `CONTRIBUTING.rst`_ document.
+
+2. Otherwise, please join the the `CMake Users List`_ and ask about
+   the expected and observed behaviors to determine if it is really
+   a bug.
+
+3. Finally, if the issue is not resolved by the above steps, open
+   an entry in the `CMake Issue Tracker`_.
+
+.. _`CMake Issue Tracker`: http://www.cmake.org/Bug
+
 Contributing
 ============