Include documentation about proposed data sources

Signed-off-by: Akashdeep Dhar <akashdeep.dhar@gmail.com>

docs/fcas/index.rst

@@ -98,5 +98,6 @@ Index
     creation_workflow
     creation_gram
     creation_fail
+    solution_datanote
     solution_workflow
     proposed_technologies

docs/fcas/solution_datanote.rst

@@ -0,0 +1,62 @@
+.. _creation_gram.rst:
+
+Planned Statistics Sources
+====
+
+For obtaining the list of all usernames
+----
+
+In contrast to the earlier approach of gathering statistics for the active 
+users available on FASJSON, this time around the statistics would need to be a
+lot more verbose and detailed. The core part that binds these statistics is the
+nature of the information collected as we would want to ensure that these 
+activities are "objectively" perceived. What looks like a contribution to a 
+certain person should look the same to others as well.
+
+The list of the all available users has been planned to be resourced from the
+authentication database itself, instead of interacting with an HTTP API like 
+FASJSON first and then letting FASJSON connect with the authentication database
+like we did before. This is to ensure that the scheduled runs for the process to
+fetch and update the list of users is not performance intensive and lesser
+time consuming in general than it was before.
+
+Previous architecture
+^^^^
+
+.. image:: ../_static/fcas-namelist-prev.png
+    :target: ../_images/fcas-namelist-prev.png
+
+Planned architecture
+^^^^
+
+.. image:: ../_static/fcas-namelist-curt.png
+    :target: ../_images/fcas-namelist-curt.png
+
+For obtaining the list of active usernames
+----
+
+`Fedora Messaging <https://fedora-messaging.readthedocs.io/>`_ keeps track of
+the activities performed on a certain set of services deployed on the community
+infrastructure. As the act of making contributions would inevitably require the
+interactions with these services - it is very likely that the contribution
+activities would cause the service to publish a message on the Fedora Messaging
+bus, should the relevant schemas be configured correctly.
+
+The historical collection of all messages published on the Fedora Messaging bus
+since the time of its deployment in production has been stored on a database
+service known as `Datanommer <https://github.com/fedora-infra/datanommer>`_ and
+this is something that can be probed into directly without including another 
+element in the system for facilitating the requests, which was previously done
+by `Datagrepper <https://apps.fedoraproject.org/datagrepper/>`_.
+
+Previous architecture
+^^^^
+
+.. image:: ../_static/fcas-actvlist-prev.png
+    :target: ../_images/fcas-actvlist-prev.png
+
+Planned architecture
+^^^^
+
+.. image:: ../_static/fcas-actvlist-curt.png
+    :target: ../_images/fcas-actvlist-curt.png