[Initiatives.wiki] Update DevOps with Flatpak

[Jordan Petridis <jpetridis src gnome org>]

commit de48a60ba373719eb0108549c83ddbf3d1c859f5
Author: Jordan Petridis <jordanpetridis protonmail com>
Date:   Tue Jul 24 22:37:55 2018 +0000

    Update DevOps with Flatpak

 DevOps-with-Flatpak.md | 11 +++++++++++
 1 file changed, 11 insertions(+)
---
diff --git a/DevOps-with-Flatpak.md b/DevOps-with-Flatpak.md
index d43b762..7a2a230 100644
--- a/DevOps-with-Flatpak.md
+++ b/DevOps-with-Flatpak.md
@@ -179,6 +179,17 @@ stop_review:
 
 ```
 
+## FAQ
+
+### Why not use the flatpak-builder one liner?
+
+`flatpak-builder --keep-build-dirs --repo=repo app org.gnome.Manifest.json`
+
+This almost does what we would want, but not quite. If you build this way it will always try to fetch your 
modules from the source specified in the manifest, but we want to use our local checkout instead. This is 
fine if you only build the `master` branch but MRs need to be able to change the source to their checkout.
+
+To achieve this we use the `--stop-at=module` argument which will build all of the dependancies up to your 
module from the manifest. Then we take over and need to install the application ourselves. This is why your 
config
+s `MESON_ARGS` variable needs to be kept in sync with your module's config options in the manifest.
+
 # Parallel installation
 For GLib & Gtk+ based apps we need to generate a different dbus id, so different versions can be installed 
and ran alongside. For that, we created the concept of "profiles" in the building phase. This is a bit tricky 
and also needs to be done all at once for the major part.