fix duplicate url key of jamstack

Author: viethung0823

topics/jamstack/index.md

@@ -9,7 +9,6 @@ url: https://jamstack.org/
 created_by: Matt Biilmann
 released: 2015
 wikipedia_url: https://en.wikipedia.org/wiki/Jamstack
-url: https://jamstack.org/what-is-jamstack/
 related: javascript, api, ssg, gatsby
 ---
 **Jamstack** (previously stylized as **JAMStack**) is a web development architecture pattern and solution stack. In other words, it is a way of thinking about how to build for the web: the UI is compiled, the frontend is fully decoupled, and data is pulled in as needed. The acronym "JAM" stands for JavaScript, API and Markup (generated by a [static site generator](/topics/ssg)).