[doc] Add blurb about large-scale model downloads

cc @n1t0 @LysandreJik @thomwolf

docs/source/installation.rst

@@ -52,6 +52,12 @@ If you want to reproduce the original tokenization process of the ``OpenAI GPT``
 If you don't install ``ftfy`` and ``SpaCy``\ , the ``OpenAI GPT`` tokenizer will default to tokenize using BERT's ``BasicTokenizer`` followed by Byte-Pair Encoding (which should be fine for most usage, don't worry).
 
 
+Note on model downloads (Continuous Integration or large-scale deployments)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+If you expect to be downloading large volumes of models (more than 1,000) from our hosted bucket (for instance through your CI setup, or a large-scale production deployment), please cache the model files on your end. It will be way faster, and cheaper. Feel free to contact us privately if you need any help.
+
+
 Do you want to run a Transformer model on a mobile device?
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^