[fractal.wiki] Update Best practices for Fractal development

[Tobias Bernard <tbernard src gnome org>]

commit 4465ed81ec1682b027e1f61cea6ed17cda494ec8
Author: Tobias Bernard <tobias bernard im>
Date:   Mon Feb 25 09:00:37 2019 +0000

    Update Best practices for Fractal development

 Best-practices-for-Fractal-development.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/Best-practices-for-Fractal-development.md b/Best-practices-for-Fractal-development.md
index d60d1f0..14b745c 100644
--- a/Best-practices-for-Fractal-development.md
+++ b/Best-practices-for-Fractal-development.md
@@ -10,7 +10,7 @@ Trivial merge requests can be merged immediately. Anything non trivial needs to
 * one reviewer has carefully checked the changes and approves them, and 48hrs have passed
 * two reviewers have carefully checked the changes and approve them
 
-
+If a merge request makes visible UI changes, include screenshots (or a screencast, if it's a more dynamic 
feature) in the description.
 
 # Code style