def add_video_to_db(video_url, thumbnail_url, video_type, object_id, username=None):
if not Video.query.filter(Video.url==video_url).count():
v = Video(url=video_url, thumbnail=thumbnail_url, video_type=video_type, object_id=object_id)
if username:
v.username=username
db.session.add(v)
db.session.commit()
