[LIVY-462][DOCS] Minor Update to the Getting Started Page

[LIVY-462](https://issues.apache.org/jira/browse/LIVY-462)

For the current version of Livy the `livy-server` script should be run with the `start` arg

Author: Alex Bozarth <ajbozart@us.ibm.com>

Closes #22 from ajbozarth/462.
diff --git a/site/get-started.md b/site/get-started.md
index d0b86d3..4931d48 100644
--- a/site/get-started.md
+++ b/site/get-started.md
@@ -40,7 +40,7 @@
 
 Then start the server with:
 
-`./bin/livy-server`
+`./bin/livy-server start`
 
 Livy uses the Spark configuration under `SPARK_HOME` by default. You can override the Spark configuration by setting the
 `SPARK_CONF_DIR` environment variable before starting Livy.