Steps 1 & 2

					<?php
// Create the Kanban board tables
function wpturbo_create_kanban_tables() {
    global $wpdb;

    $charset_collate = $wpdb->get_charset_collate();
    $table_prefix = $wpdb->prefix;
    
    // Table names
    $boards_table = $table_prefix . 'kanban_boards';
    $lists_table = $table_prefix . 'kanban_lists';
    $cards_table = $table_prefix . 'kanban_cards';
    $users_table = $table_prefix . 'kanban_users';

    // Create boards table
    $sql_boards = "
        CREATE TABLE $boards_table (
            id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
            title VARCHAR(255) NOT NULL,
            description TEXT,
            created_by BIGINT(20) UNSIGNED NOT NULL,
            created_at DATETIME NOT NULL,
            PRIMARY KEY (id),
            FOREIGN KEY (created_by) REFERENCES $users_table(id) 
                ON DELETE CASCADE
        ) $charset_collate;
    ";

    // Create lists table
    $sql_lists = "
        CREATE TABLE $lists_table (
            id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
            board_id BIGINT(20) UNSIGNED NOT NULL,
            title VARCHAR(255) NOT NULL,
            position INT NOT NULL,
            PRIMARY KEY (id),
            FOREIGN KEY (board_id) REFERENCES $boards_table(id) 
                ON DELETE CASCADE
        ) $charset_collate;
    ";

    // Create cards table
    $sql_cards = "
        CREATE TABLE $cards_table (
            id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
            list_id BIGINT(20) UNSIGNED NOT NULL,
            title VARCHAR(255) NOT NULL,
            description TEXT,
            position INT NOT NULL,
            PRIMARY KEY (id),
            FOREIGN KEY (list_id) REFERENCES $lists_table(id) 
                ON DELETE CASCADE
        ) $charset_collate;
    ";

    // Create users table
    $sql_users = "
        CREATE TABLE $users_table (
            id BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT,
            username VARCHAR(255) NOT NULL,
            email VARCHAR(255) NOT NULL,
            password VARCHAR(255) NOT NULL,
            PRIMARY KEY (id)
        ) $charset_collate;
    ";

    // Execute SQL queries to create tables
    require_once( ABSPATH . 'wp-admin/includes/upgrade.php' );
    dbDelta( $sql_boards ); // Create the boards table
    dbDelta( $sql_lists ); // Create the lists table
    dbDelta( $sql_cards ); // Create the cards table
    dbDelta( $sql_users ); // Create the users table
}
register_activation_hook( __FILE__, 'wpturbo_create_kanban_tables' );

// User Registration
function wpturbo_user_registration() {
    if ( isset( $_POST['register'] ) ) {
        $username = sanitize_text_field( $_POST['username'] );
        $email = sanitize_email( $_POST['email'] );
        $password = $_POST['password']; // Please note that this is not secure and needs to be improved

        // Perform any additional validation checks here

        // Create user record in the database
        global $wpdb;
        $users_table = $wpdb->prefix . 'kanban_users';
        $wpdb->insert(
            $users_table,
            array(
                'username' => $username,
                'email' => $email,
                'password' => $password // Please note that this is not secure and needs to be improved
            )
        );

        // Redirect to a success page or display a success message
        wp_redirect( home_url( '/registration-success/' ) );
        exit;
    }
}
add_action( 'init', 'wpturbo_user_registration' );

// User Login
function wpturbo_user_login() {
    if ( isset( $_POST['login'] ) ) {
        $username = sanitize_text_field( $_POST['username'] );
        $password = $_POST['password']; // Please note that this is not secure and needs to be improved

        // Perform user authentication here
        // You can utilize WordPress functions like wp_authenticate()

        // Redirect to the dashboard or display an error message
        wp_redirect( admin_url() );
        exit;
    }
}
add_action( 'init', 'wpturbo_user_login' );