Created a useful function to add song to song_db, and

diff --git a/songbook-editor.py b/songbook-editor.py
index 19cdab8..ab43de0 100755
--- a/songbook-editor.py
+++ b/songbook-editor.py
@@ -74,6 +74,10 @@ class interface(QtGui.QMainWindow):

         return newsong

+    def add_song_to_db(self, song):
+        self.song_db.append(song)
+        self.list_update()
+
     def savesong(self):
         need_new_song = True
         song_to_save = self.get_active_song()
@@ -85,8 +89,7 @@ class interface(QtGui.QMainWindow):
                 need_new_song = False
                 break
         if(need_new_song):
-            self.song_db.append(song_to_save)
-            self.ui.list_songs.addItem(list_item)
+            self.add_song_to_db(song_to_save)

     def save_song_to_file(self):
         filename = QtGui.QFileDialog.getSaveFileName(self, "Salva Canzone", "", "Canzoni di RobolCanzoniere (*.rcs)")