-- Create messages table
CREATE TABLE messages (
    id INT AUTO_INCREMENT PRIMARY KEY,
    sender_id INT NOT NULL,
    receiver_id INT NOT NULL,
    content TEXT NOT NULL,
    sent_at DATETIME DEFAULT CURRENT_TIMESTAMP,
    delivered BOOLEAN DEFAULT FALSE,
    FOREIGN KEY (sender_id) REFERENCES users(id),
    FOREIGN KEY (receiver_id) REFERENCES users(id)
);