Add information on updating [certbot|letsencrypt]-auto
diff --git a/docs/contributing.rst b/docs/contributing.rst
index de520dc0e5f..5ad4bd9e014 100644
--- a/docs/contributing.rst
+++ b/docs/contributing.rst
@@ -324,6 +324,48 @@ Steps:
 7. Submit the PR.
 8. Did your tests pass on Travis? If they didn't, fix any errors.
 
+
+Updating certbot-auto and letsencrypt-auto
+==========================================
+Updating the scripts
+--------------------
+Developers should *not* modify the ``certbot-auto`` and ``letsencrypt-auto`` files
+in the root directory of the repository.  Rather, modify the
+``letsencrypt-auto.template`` and associated platform-specific shell scripts in
+the ``letsencrypt-auto-source`` and
+``letsencrypt-auto-source/pieces/bootstrappers`` directory, respectively.
+
+Building letsencrypt-auto-source/letsencrypt-auto
+-------------------------------------------------
+Once changes to any of the aforementioned files have been made, the
+``letesncrypt-auto-source/letsencrypt-auto`` script should be updated.  In lieu of
+manually updating this script, run the build script, which lives at
+``letsencrypt-auto-source/build.py``:
+
+.. code-block:: shell
+
+   python letsencrypt-auto-source/build.py
+
+Running ``build.py`` will update the ``letsencrypt-auto-source/letsencrypt-auto``
+script.  Note that the ``certbot-auto`` and ``letsencrypt-auto`` scripts in the root
+directory of the repository will remain **unchanged** after this script is run.
+Your changes will be propagated to these files during the next release of
+Certbot.
+
+Opening a PR
+------------
+When opening a PR, ensure that the following files are committed:
+
+1. ``letsencrypt-auto-source/letsencrypt-auto.template`` and
+   ``letsencrypt-auto-source/pieces/bootstrappers/*``
+2. ``letsencrypt-auto-source/letsencrypt-auto`` (generated by ``build.py``)
+
+It might also be a good idea to double check that **no** changes were
+inadvertently made to the ``certbot-auto`` or ``letsencrypt-auto`` scripts in the
+root of the repository.  These scripts will be updated by the core developers
+during the next release.
+
+
 Updating the documentation
 ==========================
 

Added instructions on how to update `letsencrypt-auto`.  Included information on running `build.py` and stressed that `certbot-auto`/`letsencrypt-auto` in the root directory shouldn't be updated; hopefully this helps cut down on 
> thanks for the PR... but please don't modify `certbot-auto`/`letsencrypt-auto` directly

responses to PRs.  

Fixes #3703