Merge PR #532 into 16.0

Signed-off-by lmignon

Author: OCA-git-bot

fs_attachment/readme/USAGE.rst

@@ -226,3 +226,14 @@ Tips & Tricks
   instance will still be read from the production storage. Be careful to adapt the
   configuration of your storage to the production environment to make it read only.
   (The use of server environment files is a good way to do so).
+
+* When enabling `Use As Default For Attachment` you must be aware that this
+  option applies from the point when the `fs_attachment` has been loaded by
+  Odoo. This means that some attachments (such as icons)  created during the
+  update of modules that are loaded before `fs_attachment` will still be stored
+  in the location defined in the `ir_attachment.location` system parameter
+  (which is `file` by default, meaning the regular on-disk `filestore`
+  directory). 
+  
+  A simple way to work around this issue is to set the `ir_attachment.location`
+  System Parameter record to `db`.