added example code for using AqCGI.

README.md

@@ -15,6 +15,7 @@ AqCGI only depends on libgwenhywfar (see [gwenhywfar](https://www.aquamaniac.de/
 
 ### Build
 Download and unpack tar.gz file, CD into the unpacked folder and build like this:
+
 ```
 mkdir build
 cd build
@@ -23,3 +24,22 @@ gwbuild -jNN (with NN being the number of parallel processes to use, e.g. 4 if c
 sudo gwbuild -i
 ```
 
+## Use AqCGI
+
+Working with AqCGI is as simple as this (in your main() function):
+
+  ```
+  AQCGI_REQUEST *rq;
+
+  DBG_ERROR(NULL, "Init CGI");
+  AQCGI_Init();
+  rq=AQCGI_ReadRequest();
+  if (rq) {
+    // do something with the request
+    
+    AQCGI_SendResponseWithStatus(rq, 200, "Ok");
+    AQCGI_Request_free(rq);
+  }
+  AQCGI_Fini();
+  ```
+