Update server_config.md

doc/server_config.md

@@ -72,7 +72,7 @@ Duplicate config.ini in server/preprocessing/conf/ and rename it to config_local
 * general->path: Relative path to the client visualization. Needs to be in the public_html/www directory.
 * general->images_path: Full path to the images directory for the client. Needs to be in the public_html/www directory. **Make sure that your webserver has write access to this directory.**
 * general->services_path: Relative path to the client REST services. Needs to be in the public_html/www directory.
-* general->api_url: URL to backend API as provided, or default localhost
+* general->api_url: URL to backend API as provided, or default localhost, e.g. `http://127.0.0.1/api/`
 * calculation->binary: Path to RScript binary
 * connection->sqlite_db: Full path to the sqlite datatabase file. For development purposes, duplicate headstart.sqlite in server/storage/ and rename it to a filename of your choice. Enter the path to this file here. **Make sure that your webserver has write & execute permissions to this file and the containing directory.**
 * connection->linkedcat_solr: URL to the SOLR server, without protocol or additional paths