Fix database unique issue

main.py

@@ -110,7 +110,9 @@ if __name__ == '__main__':
                 if broadcast:
                     view.broadcast(message)
                 # store new scratching
-                query = "INSERT INTO horses(venue, race_date, race, horse) VALUES(%s, %s, %s, %s)"
+                query = """INSERT INTO horses(venue, race_date, race, horse) 
+                    VALUES(%s, %s, %s, %s)
+                    ON CONFLICT(venue, race_date, race, horse) DO NOTHING;"""
                 cursor.execute(query, (scratching.venue, scratching.date,
                                        scratching.race, scratching.horse))
                 db.commit()