Add fedpkg document to dist-git ARC investigation

Adds fedpkg related investigation to dist-git decoupling documentation.

Signed-off-by: Michal Konecny <mkonecny@redhat.com>

docs/dist-git-move/fedpkg.rst

@@ -0,0 +1,55 @@
+.. _fedpkg:
+
+Pagure Dist Git Interactions With fedpkg
+====
+
+`Fedpkg <https://pagure.io/fedpkg>`_ is a CLI tool for packagers that allows
+them to work with packages in Fedora package workflow.
+
+Possible Interactions
+----
+
+The following are a set of documented interactions possible between Pagure Dist
+Git and fedpkg.
+
+Lookaside cache
+^^^^
+
+- fedpkg is using lookaside cache that is located on same server as dist git
+  https://src.fedoraproject.org/repo/pkgs
+
+API calls
+^^^^
+
+- Fedpkg is calling dist git API endpoint ``api/0/fork`` when creating fork of
+  the project.
+- Fedpkg is calling dist git API endpoint ``_db/anitya/<namespace>/<package_name>``
+  for disabling monitoring for repository.
+
+Git interactions
+^^^^
+
+- Fedpkg works with cloned dist git repositories using standard
+git commands.
+
+Changes proposed
+----
+
+In order to switch out Pagure Dist Git for an alternative that provides a
+relatively compatible API pattern, the following changes must be made in the
+places mentioned below.
+
+Necessary
+^^^^
+
+- In case URL will be changed default configuration distributed with
+  fedpkg RPM package needs to be updated.
+
+  * `fedpkg.conf <https://pagure.io/fedpkg/blob/master/f/conf/etc/rpkg/fedpkg.conf>`_
+    for production fedpkg
+  * `fedpkg-stage.conf <https://pagure.io/fedpkg/blob/master/f/conf/etc/rpkg/fedpkg-stage.conf>`_
+    for staging fedpkg
+
+- The lookaside cache needs to be still available. In case the location will be different
+  some changes will be needed with working the lookaside cache in fedpkg as currently it
+  expects the URL is same as for dist git.

docs/dist-git-move/index.rst

@@ -45,6 +45,7 @@ Index
 
     ci
     copr
+    fedpkg
     hotness
     notifications
     toddlers