connection pool reference (#616)

* add link in index to external jwt
* change pgrst errors location for better reading

docs/index.rst

@@ -148,6 +148,12 @@ Technical references for PostgREST's functionality.
 
    transactions.rst
 
+.. toctree::
+   :caption: Connection Pool
+   :hidden:
+
+   connection_pool.rst
+
 .. toctree::
    :caption: Configuration
    :hidden:
@@ -169,6 +175,7 @@ Technical references for PostgREST's functionality.
 - :doc:`Authentication <auth>`
 - :doc:`API <api>`
 - :doc:`Transactions <transactions>`
+- :doc:`Connection pool <connection_pool>`
 - :doc:`configuration`
 - :doc:`Schema Cache <schema_cache>`
 - :doc:`Errors <errors>`
@@ -235,6 +242,7 @@ PostgREST has a growing ecosystem of examples, libraries, and experiments. Here
 
    ecosystem.rst
 
+* :ref:`external_jwt`
 * :ref:`community_tutorials`
 * :ref:`templates`
 * :ref:`eco_example_apps`