[gnome-todo] window: add org-gnome-Todo style class

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit dc80a70d2f352642cd6e5fc58f372fa6301ee3ba
Author: alex285 <alexis diavatis hotmail com>
Date:   Fri Dec 8 13:23:38 2017 +0200

    window: add org-gnome-Todo style class
    
    Currently there is no way for a theme to add some specific styles (eg colors) on Todo widgets, without 
upstreaming their CSS.
    This commit adds the org-gnome-Todo CSS class on the main window, as a helper selector. (See bug #133)

 data/ui/window.ui | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/data/ui/window.ui b/data/ui/window.ui
index 90e39ab..464075b 100644
--- a/data/ui/window.ui
+++ b/data/ui/window.ui
@@ -6,6 +6,9 @@
     <property name="can_focus">False</property>
     <property name="default_width">800</property>
     <property name="default_height">600</property>
+    <style>
+      <class name="org-gnome-Todo"/>
+    </style>
     <child>
       <object class="GtkOverlay" id="overlay">
         <property name="visible">True</property>