Restructure graph view and add background color property

app/src/main.c

@@ -32,6 +32,7 @@ int main(int argc, char **argv)
 {
 	GtkWidget *main_window;
 	GtkWidget *graph_view;
+	GdkRGBA color;
 
 	gtk_init(&argc, &argv);
 
@@ -41,8 +42,15 @@ int main(int argc, char **argv)
 
 	graph_view = gtk_graph_view_new();
 	gtk_container_add(GTK_CONTAINER(main_window), graph_view);
-
+	gtk_widget_show(graph_view);
 	gtk_widget_show_all(main_window);
+
+	color.red = 0.6;
+	color.green = 0.4;
+	color.blue = 0.1;
+	color.alpha = 1.0;
+	gtk_graph_view_set_background_color(GTK_GRAPH_VIEW(graph_view), &color);
+
 	gtk_main();
 
 	return 0;