✨ Implement Google OAuth authentication and event claiming functionality

• Added Google OAuth integration with OmniAuth for user authentication.


• Created Users table with fields for email, name, Google ID, and avatar URL.


• Updated Events table to include a user reference for claimed events.


• Implemented SessionsController for handling sign-in, sign-out, and failure actions.


• Created EventClaimsController to manage claiming events by users.


• Updated views for sign-in, event claiming, and event management.


• Enhanced header and footer for user authentication state.


• Added routes for authentication and event claiming.


• Configured OmniAuth initializer for Google OAuth.


• Updated application layout and styles for improved user experience.