Add EE Guide link to Installing collections page (#308)

docs/docsite/rst/collections_guide/collections_installing.rst

@@ -7,6 +7,12 @@ Installing collections
 
   If you install a collection manually as described in this paragraph, the collection will not be upgraded automatically when you upgrade the ``ansible`` package or ``ansible-core``.
 
+Installing collections in containers
+------------------------------------
+
+You can install collections with their dependencies in containers known as execution environments.
+See `Getting started with Execution Environments <https://docs.ansible.com/ansible/devel/getting_started_ee/index.html>`_ for details.
+
 Installing collections with ``ansible-galaxy``
 ----------------------------------------------
 
@@ -123,4 +129,4 @@ Installing a collection from a git repository
 Configuring the ``ansible-galaxy`` client
 ------------------------------------------
 
-.. include:: ../shared_snippets/galaxy_server_list.txt
+.. include:: ../shared_snippets/galaxy_server_list.txt