Introduce changelog metadata in commit messages

Thanks to this, changelog can be automatically generated while staying
useful.

.git-commit-template

@@ -0,0 +1,16 @@
+
+
+# In addition to regular commit message, you can uncomment and fill in the
+# following to include this change in the released RPM package changelog:
+
+# = changelog =
+# msg:
+# type:
+# resolves:
+# related:
+
+# msg        = message to be included in the changelog
+# type       = one of: bugfix/enhancement/security
+# resolves   = URLs to bugs or issues resolved by this commit
+# related    = URLs to any related bugs or issues
+

README.rst

@@ -88,7 +88,25 @@ Here's the most direct way to get your work merged into the project.
 1. Fork the project
 #. Clone down your fork
 #. Implement your feature or bug fix and commit changes
-#. If you reported a bug or you know it fixes existing bug at `Red Hat bugzilla <https://bugzilla.redhat.com/>`_, append ``(RhBug:<bug_id>)`` to your commit message
+#. If the change fixes a bug at `Red Hat bugzilla <https://bugzilla.redhat.com/>`_, or if it is important to the end user, add the following block to the commit message::
+
+    = changelog =
+    msg:           message to be included in the changelog
+    type:          one of: bugfix/enhancement/security (this field is required when message is present)
+    resolves:      URLs to bugs or issues resolved by this commit (can be specified multiple times)
+    related:       URLs to any related bugs or issues (can be specified multiple times)
+
+   * For example::
+
+       = changelog =
+       msg: Verify GPG signatures when running dnf-automatic
+       type: bugfix
+       resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1793298
+
+   * For your convenience, you can also use git commit template by running the following command in the top-level directory of this project::
+
+       git config commit.template ./.git-commit-template
+
 #. In special commit add your name and email under ``DNF CONTRIBUTORS`` section in `authors file <https://github.com/rpm-software-management/dnf/blob/master/AUTHORS>`_ as a reward for your generosity
 #. Push the branch up to your fork
 #. Send a pull request for your branch