added the pony database

lyrics/db/__init__.py

@@ -0,0 +1,19 @@
+from datetime import date
+from pony.orm import *
+
+db = Database("sqlite", "lyrics.sqlite", create_db=True)
+
+class Artist(db.Entity):
+    name = Required(unicode)
+    songs = Set("Song")
+
+class Song(db.Entity):
+    artists = Set(Artist)
+    name = Required(unicode)
+    done = Optional(date)
+    youtube = Optional(unicode)
+    lyric = Required("Lyric")
+
+class Lyric(db.Entity):
+    text = Required(LongUnicode)
+    song = Required(Song)