make window start maximized

data/ui/sernatur.window.ui

@@ -21,6 +21,9 @@ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
     <property name="title">SERNATUR</property>
     <property name="icon_name">sernatur</property>
     <property name="show_menubar">False</property>
+    <child>
+      <placeholder/>
+    </child>
     <child>
       <object class="GtkImage">
         <property name="visible">True</property>

src/sernatur.vala

@@ -37,6 +37,7 @@ namespace Sernatur {
 		 */
 		public override void activate () {
 			window = new MainWindow (this);
+			window.maximize ();
 			window.present ();
 		}