update doc following fresh install

doc/1.production.md

@@ -42,13 +42,16 @@ python -m flatisfy build-data --config config/config.json -v
 python -m flatisfy import --config config/config.json -v
 ```
 
-_Note_: In the config, you should set `data_directory` to the absolute path of
+_Note 1_: In the config, you should set `data_directory` to the absolute path of
 the `data` directory created below. This directory should be writable by the
 user running Flatisfy. You should also set `modules_path` to the absolute path
 to the `modules` folder under the previous `weboob` clone. Finally, the last
 `import` command can be `cron`-tasked to automatically fetch available
 housings posts periodically.
 
+_Note 2_: As of 2019-03-13, building the webapp requires libpng-dev to be able to build pngquant-bin. On Debian Stretch (tested with Node v11.11.0):
+
+    sudo apt install libpng-dev
 
 ## Use an alternative Bottle backend (production)
 
@@ -221,3 +224,26 @@ setup. You should also set the `.htpasswd` file with users and credentials.
 _Note_: This vhost is really minimalistic and you should adapt it to your
 setup, enforce SSL ciphers for increased security and do such good practices
 things.
+
+### If database is in read only
+
+In the case of you have a "flatisfy" user, and another user runs the webserver, for instance "www-data", you should have problems with the webapp reading, but not writing, the database. Workaround (Debian):
+
+Add www-data in flatisfy group:
+
+    sudo usermod -a -G flatisfy www-data
+
+Chmod data dir + DB file:
+
+    sudo chmod 775 data
+    sudo chmod 664 data/flatisfy.db
+
+Edit /etc/uwsgi/apps-available/flatisfy.ini and add:
+
+    chmod-socket = 664
+
+Restart:
+
+```bash
+systemctl restart uwsgi
+```