added git clone to setup

stretch_rtab/README.md

@@ -9,6 +9,9 @@
 Use `rosdep` to install the required packages.
 
 ```bash
+    cd ~/catkin_ws/src
+    git clone https://github.com/NateWright/stretch_ros.git
+    git clone https://github.com/pal-robotics/realsense_gazebo_plugin
     cd ~/catkin_ws
     rosdep install --from-paths src --ignore-src -r -y
     catkin_make