[fractal.wiki] Update Best practices for Fractal development

[Julian Sparber <jsparber src gnome org>]

commit 8950d338abaea35e2cad547c057c6ff33ea3ba6b
Author: Julian Sparber <julian sparber net>
Date:   Sat Jan 19 11:03:21 2019 +0000

    Update Best practices for Fractal development

 Best-practices-for-Fractal-development.md | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/Best-practices-for-Fractal-development.md b/Best-practices-for-Fractal-development.md
index 59fc270..d60d1f0 100644
--- a/Best-practices-for-Fractal-development.md
+++ b/Best-practices-for-Fractal-development.md
@@ -18,4 +18,6 @@ Trivial merge requests can be merged immediately. Anything non trivial needs to
 * Use `.unwrap_or_default()` for `Option` and `Result` over `unwrap_or(neutral_value)`. It won't work if the 
contained type doesn't implement the Default trait.
 * Prefer to process the contained value in an Option or Result with combinators and unwrap at the end, 
unless it makes the code difficult to read because of doing it that way.
 * Don't be afraid to go beyond the simpler types or even create new ones. They give semantic meaning to 
values and thus let the compiler check for the correctness of the code at that level if used appropriately.
+* AppOp is a legacy struct which shouldn't be used anymore in new code, we work on removing it.
+* In fractal-gtk we depend on gtk and glib, try to use glib methods to solve problems where ever possible.