Updated README

Author: rohe

README.rst

@@ -38,3 +38,15 @@ testing. To run the tests on your system's version of python
 
 To run tests in multiple python environments, you can use
 `pyenv <https://github.com/yyuu/pyenv>`_ with `tox <https://tox.readthedocs.io/en/latest/>`_.
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+Please contribute!
+==================
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+To help out, you could:
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+1. Test and report any bugs or other difficulties.
+2. Implement missing features.
+3. Write more unit tests.
+
+**If you have the time and inclination I'm looking for Collaborators**