In example request, show example using curl

This clarifies the exact way to construct this request. It seems that
some users have taken the existing documentation to mean that the
request should be sent from the browser, to the web server. This example
clarifies how to send this compile request directly to the clsi server.

services/clsi/README.md

@@ -89,9 +89,16 @@ The CLSI is based on a JSON API.
 }
 ```
 
+With `curl`, if you place the above json in a file called `data.json`, the request would look like this:
+
+``` shell
+$ curl -X POST -d @data.json localhost:3013/project/<id>/compile
+```
+
 You can specify any project-id in the URL, and the files and LaTeX environment will be persisted between requests.
 URLs will be downloaded and cached until provided with a more recent modified date.
 
+
 #### Example Response
 
 ```javascript