public function create_tables() {

		global $wpdb;

		$charset_collate = $wpdb->get_charset_collate();

		$table_name = $wpdb->prefix . 'efg_custom_rating';

		if ( $wpdb->get_var( "SHOW TABLES LIKE '$table_name'" ) != $table_name ) {
			$sql = "CREATE TABLE $table_name (
	          id      mediumint(9) NOT NULL AUTO_INCREMENT,
	          post_id mediumint(9) NOT NULL,
	          ip      varchar(45)  NOT NULL,
	          vote    int(2)       NOT NULL,
	          PRIMARY KEY  (id)
	        ) $charset_collate;";

			require_once( ABSPATH . 'wp-admin/includes/upgrade.php' );

			dbDelta( $sql );
		}
	}