title: country based shipping module in opencart 2.1
body: <p>I want to create module or extension, in which i want following feature.</p>
  
  <p>1- when user come from new york and amount more than 500$ then he can get free shipping, i mean there will be a radio button add in delivery step.
  2- when user come out side new york and amount more than 700$ then can get free shipping. </p>
  
  <p>But i don't know how can i do it, i also try to do using coupon code module but there is not link between zone and coupon code. Can any one please guide me regarding this module. I would like to appreciate</p>