add-wc-payment-gateway-plugin-base.php

<?php
/**
 * Plugin Name: WooCommerce <enter name> Gateway
 * Plugin URI: https://wbcomdesigns.com/
 * Description: Extends WooCommerce with an <enter name> gateway.
 * Version: 1.0
 * Author: Wbcomdesigns
 * Author URI: https://wbcomdesigns.com/
 */
function wb_woocommerce_gateway_name_init() {
	if ( ! class_exists( 'WC_Payment_Gateway' ) ) {
		return;
	}
	/**
	 * Localisation.
	 */
	load_plugin_textdomain( 'wc-gateway-name', false, dirname( plugin_basename( __FILE__ ) ) . '/languages' );

	/**
	 * Gateway class
	 */
	class WC_Gateway_Name extends WC_Payment_Gateway {

		// Go wild in here.
	}

	/**
	 * Add the Gateway to WooCommerce.
	 **/
	function wb_woocommerce_add_gateway_name_gateway( $methods ) {
		$methods[] = 'WC_Gateway_Name';
		return $methods;
	}

	add_filter( 'woocommerce_payment_gateways', 'wb_woocommerce_add_gateway_name_gateway' );
}
add_action( 'plugins_loaded', 'wb_woocommerce_gateway_name_init', 0 );