Document updating patch

Author: spoorcc

dfetch/commands/diff.py

@@ -52,8 +52,30 @@
 ======================
 If you have further changes to a project with a patch, you can update the patch by first reversing the patch, using the
 ``--apply`` and ''--directory`` arguments as shown above. To reverse the patch you also require the ``-R``. This will
-return the project to the state before the patch was applied. If you commit this base project, then re-apply the patch
- and any additional changes, you can generate a new patch with the latest state.
+return the project to the state before the patch was applied. You can then stage the project and re-apply the patch to
+the project to have the patch
+
+.. code-block:: sh
+
+   # First apply the reverse patch
+   git apply --verbose --directory='some-project' -R some-project.patch
+
+   # Stage the project in its unpatched state
+   git add some-project.patch
+
+   # Re-apply the patch
+   git apply --verbose --directory='some-project' some-project.patch
+
+Now you can make further changes to the project, and re-generate the patch using the raw git command as shown above.
+
+.. code-block:: sh
+
+   # Generate the patch from the directory again
+   cd some-project
+   git diff --relative --binary --no-ext-diff --no-color . > ../some-project.patch
+
+   # Force a fetch and update the patch to test your changes
+   dfetch update -f some-project
 
 """