Add an acknowledgement section in the README. Thank @tkf, @dbrgn and @gvanrossum for their contributions.

README.rst

@@ -175,6 +175,17 @@ For more detailed information visit the `testing documentation
 <https://jedi.readthedocs.org/en/latest/docs/testing.html>`_
 
 
+Acknowledgements
+================
+
+- Takafumi Arakaki (@tkf) for creating a solid test environment and a lot of
+  other things.
+- Danilo Bargen (@dbrgn) for general housekeeping and being a good friend :).
+- Guido van Rossum (@gvanrossum) for creating the parser generator pgen2
+  (originally used in lib2to3).
+
+
+
 .. _jedi-vim: https://github.com/davidhalter/jedi-vim
 .. _youcompleteme: http://valloric.github.io/YouCompleteMe/
 .. _Jedi.el: https://github.com/tkf/emacs-jedi