Webshop and E-commerce in ERPNext 15

Hi Everyone,

I need to asking about webshop and e-commerce?
Beween webshop and e-commerce is same module or no?

Then i am currently install webshop with erpnext, and payment module, it is little bit difffrent between payment module integrate in documentation and payment module i installed.

in payment module bundling webshop just like this

So… how i can inttegrate with payment gateway? where i can store api key?