Corrected updated relationships

movies.py

@@ -13,7 +13,7 @@ class Movie(Persisted):
     budget = Column(Integer)
     gross_revenue = Column(Integer)
     opening_date = Column(Date)
-    genres = relationship('Genre', uselist=True, secondary='movie_genres', viewonly=True)
+    genres = relationship('Genre', uselist=True, secondary='movie_genres', back_populates='movies')
     reviews = relationship('Review', uselist=True, back_populates='movie')
 
 
@@ -30,7 +30,7 @@ class Genre(Persisted):
     __tablename__ = 'genres'
     genre_id = Column(Integer, primary_key=True)
     name = Column(String(256), nullable=False)
-    movies = relationship('Movie', uselist=True, secondary='movie_genres', viewonly=True)
+    movies = relationship('Movie', uselist=True, secondary='movie_genres', back_populates='genres')
 
 
 class MovieGenre(Persisted):