Complete release instruction

setup.py

@@ -6,6 +6,7 @@ To create the package for pypi.
 1. Change the version in __init__.py, setup.py as well as docs/source/conf.py. Remove the master from the links in
    the new models of the README:
    (https://huggingface.co/transformers/master/model_doc/ -> https://huggingface.co/transformers/model_doc/)
+   then run `make fix-copies` to fix the index of the documentation.
 
 2. Unpin specific versions from setup.py that use a git install.