README.md in gir_ffi-gtk-0.7.1 vs README.md in gir_ffi-gtk-0.7.2

@@ -22,9 +22,25 @@
     GObject.signal_connect(win, "destroy") { Gtk.main_quit }
     Gtk.main
 
 See the `examples/` directory for more examples.
 
+## Requirements
+
+First, make sure the `ffi` gem is properly installed. See its documentation for
+the necessary requirements.
+
+GirFFI-Gtk itself depends on the GirFFI gem, and the gobject-introspection and
+gtk+ libaries.
+
+For debian-like systems, try the following for Gtk+ 3:
+
+    apt-get install libgirepository1.0-dev gobject-introspection gir1.2-gtk-3.0
+
+and for Gtk+ 2:
+
+    apt-get install libgirepository1.0-dev gobject-introspection gir1.2-gtk-2.0
+
 ## Install
 
     gem install gir_ffi-gtk
 
 ## License