[gnome-builder] update CONTRIBUTING.md

[Christian Hergert <chergert src gnome org>]

commit 148ab0104ea6689fb0572fe4736367122a866fd7
Author: Christian Hergert <chergert redhat com>
Date:   Wed Jan 31 05:37:58 2018 -0800

    update CONTRIBUTING.md

 CONTRIBUTING.md | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)
---
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 96a43d6c6..eb1e83c6c 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -12,11 +12,11 @@ that do this for fun. Be respectful and assume the best of each other.
 ## Filing a bug
 
 Please file bugs for issues, enhancements and features on
-[our Bugzilla](https://bugzilla.gnome.org/enter_bug.cgi?product=gnome-builder)
-bug tracker.
+[our bug tracker](https://gitlab.gnome.org/GNOME/gnome-builder/issues).
 
-To submit a patch, file a bug and attach your patch to the bug.
-Someone will review your patch shortly after doing so.
+Create a
+[Merge Request](https://gitlab.gnome.org/GNOME/gnome-builder/merge_requests)
+and we'd be happy to review your patch and help you get it merged.
 
 ## Asking for Help
 
@@ -70,6 +70,8 @@ example_object_get_widget (ExampleObject  *object,
 }
 ```
 
+You may omit curly-braces for single-line conditionals.
+
 Please use new-style Object declarations such as `G_DECLARE_FINAL_TYPE()` or `G_DECLARE_DERIVABLE_TYPE()`.
 Unless you intend to subclass the object, make the object final.
 
@@ -92,6 +94,8 @@ These include:
  * `g_steal_pointer()`
  * `g_clear_object()` and `g_clear_pointer()`
 
+We prefer that you zero fields in structures when freeing the contents.
+
 ## Documentation
 
 Most functions should be obvious what they do from the object type, name, and parameters.