updated readme and dep repo list (ros-drivers#8)

* updated readme and depo repo list

* clone ros2-devel branch for urg_node

Author: aswinthomas

README.md

@@ -1,4 +1,29 @@
 urg_node
 ===================
 
-ROS wrapper for the Hokuyo urg_c library.
+ROS wrapper for the Hokuyo urg_c library.
+
+## Build instructions (from source)
+Install ros2 from source as per instructions [here](https://github.com/ros2/ros2/wiki/Linux-Development-Setup)
+
+Create a folder for urg and clone this repo
+
+```
+mkdir -p ~/ros2_ws/src/urg
+cd ~/ros2_ws/src/urg
+git clone -b ros2-devel https://github.com/bponsler/urg_node
+```
+Clone dependencies 
+```
+cd ~/ros2_ws/src/urg/urg_node
+vcs import ../ < urg.repos
+```
+
+Finally build
+
+```
+cd ~/ros2_ws
+src/ament/ament_tools/scripts/ament.py build
+
+```
+

urg.repos

@@ -0,0 +1,25 @@
+repositories:
+  diagnostics:
+    type: git
+    url: https://github.com/bponsler/diagnostics
+    version: ros2-devel
+  laser_proc:
+    type: git
+    url: https://github.com/bponsler/laser_proc
+    version: ros2-devel
+  ros2_console:
+    type: git
+    url: https://github.com/bponsler/ros2_console
+    version: master
+  ros2_time:
+    type: git
+    url: https://github.com/bponsler/ros2_time
+    version: master
+  urg_c:
+    type: git
+    url: https://github.com/bponsler/urg_c
+    version: ros2-devel
+  urg_node_msgs:
+    type: git
+    url: https://github.com/bponsler/urg_node_msgs
+    version: master