iluwatar#297 Create README.md

Author: TylerMcConville

api-gateway/README.md

@@ -0,0 +1,28 @@
+---
+layout: pattern
+title: API Gateway
+folder: api-gateway
+permalink: /patterns/api-gateway/
+categories: Other
+tags:
+- Java
+- Difficulty-Beginner
+
+## Intent
+
+Aggregate calls to microservices in a single location: the API Gateway. The user makes a single
+call to the API Gateway, and the API Gateway then calls each relevant microservice.
+
+![alt text](./etc/api-gateway.png "API Gateway")
+
+## Applicability
+
+Use the API Gateway pattern when
+
+* you're also using the Microservices pattern and need a single point of aggregation for your
+microservice calls
+
+## Credits
+
+* [microservices.io - API Gateway](http://microservices.io/patterns/apigateway.html)
+* [NGINX - Building Microservices: Using an API Gateway](https://www.nginx.com/blog/building-microservices-using-an-api-gateway/)