Update README.md

Added ReadMe file to describe the application

README.md

@@ -16,6 +16,10 @@ Features:
 7. Logout: Users can securely log out of the app, ensuring that their movie data is protected and only accessible when they are logged in.
 8. Data Management with Supabase: The app uses Supabase for database management and user authentication. This ensures secure and reliable data storage and retrieval.
 
+Design Patterns:
+1.Singleton Pattern: Used in `MauiProgram.cs` to ensure that only one instance of services like `Supabase.Client`, `MoviesListingViewModel`, `AuthService`, and `DataService` is created and used throughout the application.
+2.Observer Pattern: Implemented in all ViewModel files using the `ObservableObject` base class and `ObservableCollection<Movie>` from the CommunityToolkit.Mvvm package. This allows the UI to be notified of changes in the data.
+
 Summary of Features Demonstrated in the Video
 User Authentication: Demonstration of both login and sign-up processes, showcasing the user authentication flow.
 Movie Listing Page: Viewing the list of added movies with details such as title, director, and poster image.