Update README.rst

Author: gamdow

README.rst

@@ -3,5 +3,8 @@ Magnics
 
 .. image:: https://travis-ci.org/computationalmodelling/magnics.svg?branch=master
     :target: https://travis-ci.org/computationalmodelling/magnics
+    
+.. image:: https://readthedocs.org/projects/fidimag/badge/?version=latest
+    :target: https://readthedocs.org/projects/fidimag/badge/?badge=latest
 
 Magnics is Python micromagnetics software using `FEniCS <www.fenicsproject.org/>`_.