Add hotness doc to dist-git-move investigation

Document hotness interactions with dist-git in Dist Git ARC investigation.

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

docs/dist-git-move/hotness.rst

@@ -0,0 +1,49 @@
+.. _hotness:
+
+Pagure Dist Git Interactions With The New Hotness
+====
+
+Possible Interactions
+----
+
+The following are a set of documented interactions possible between Pagure Dist
+Git and The New Hotness.
+
+Validations
+^^^^
+
+- Checking the monitoring setting by calling dist-git `_dg/anitya/rpms/<package_name>` API in
+  `pagure module <https://github.com/fedora-infra/the-new-hotness/blob/master/hotness/validators/pagure.py>`_
+- Checking the retirement status by HTTP GET request for `dead.package` in
+  `pagure module <https://github.com/fedora-infra/the-new-hotness/blob/master/hotness/validators/pagure.py>`_
+
+Scratch builds
+^^^^
+
+- hotness is doing the scratch builds if requested by users in
+  `koji module <https://github.com/fedora-infra/the-new-hotness/blob/master/hotness/builders/koji.py#L119>`_.
+  It uses standard git commands (clone, commit) when preparing the scratch build
+
+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
+placed mentioned below.
+
+Necessary
+^^^^
+
+- Change the
+  `configuration <https://pagure.io/fedora-infra/ansible/blob/main/f/roles/openshift-apps/the-new-hotness/templates/config.toml>`_
+  to point to new dist-git instance.
+
+Unnecessary
+^^^^
+
+- As hotness is mostly using just plain HTTP, git interactions with dist-git it's not necessary
+  to change much. Only the monitoring settings needs to be provided somewhere.
+- Change the default value for `dist_git_url` in
+  `config module <https://github.com/fedora-infra/the-new-hotness/blob/master/hotness/config.py>`_.
+  As this could be set in configuration it's not necessary to do that, but it would be nice to
+  change it to new git forge.

docs/dist-git-move/index.rst

@@ -43,6 +43,7 @@ Index
 .. toctree::
     :maxdepth: 1
 
+    hotness
     notifications
 
 Conclusions