Some more docs

DEVELOPMENT.md

@@ -9,7 +9,13 @@ or, if you have already cloned it, get submodules contents :
 git submodule init; git submodule update
 ```
 
-# Run in local
+# Test local code
+
+## Test-run in container rebuilt from local repo
+
+You may edit the code in your local copy of the repo, rebuild the
+container, and test the changes:
+
 ```
 make clean
 FLAVOR=lxqt ARCH=amd64 IMAGE=ubuntu:18.04 make build
@@ -17,6 +23,10 @@ make run
 ```
 
 ## develop backend
+
+You may wish to work on the backend app. As the "make run" makes sure
+to mount the current dir contents under /src in the container, you can
+proceed as such (no compilation of the Python code):
 ```
 make shell
 supervisorctl -c /etc/supervisor/supervisord.conf stop web
@@ -25,6 +35,7 @@ cd /src/image/usr/local/lib/web/backend
 ```
 
 ## develop frontend
+
 ```
 cd web
 yarn add