updated README

Signed-off-by: Harsh Deshpande <harshavardhan.deshpande@ipa.fraunhofer.de>

README.md

@@ -419,3 +419,52 @@ This should start printing text like `I heard: [hello world ...]` with a timesta
 ros2 service call /add_two_ints example_interfaces/srv/AddTwoInts "{a: 1, b: 2}"
 ```
 If all is well, the output should contain `example_interfaces.srv.AddTwoInts_Response(sum=3)`
+
+
+# Action bridge
+
+This bridge extends the `ros1_bridge` to action interface. The bridge works in both directions, meaning an action goal can be sent from ROS1 client to ROS2 server, or from ROS2 client to ROS1 server.
+
+The arguments for `action_bridge` node are: 
+`direction`: from client (`ros1` or `ros2`)
+e.g.:
+- `ROS1` client to `ROS2` server --> `direction` = `ros1`
+- `ROS2` client to `ROS1` server --> `direction` = `ros2` 
+
+`package`: package of the `ROS1` server node 
+`type`: action interface type of `ROS1` 
+`name`: action name
+
+For sending goals from ROS2 action client to ROS1 action server
+```
+# Terminal 1 -- action bridge
+# Make sure roscore is already running
+source <ros1_bridge-install-dir>/setup.bash
+ros2 run ros1_bridge action_bridge ros1 actionlib_tutorials Fibonacci fibonacci
+
+# Terminal 2 -- ROS1 action server
+source <ros1-install-dir>/setup.bash
+rosrun actionlib_tutorials fibonacci_server
+
+# Terminal 3 -- ROS2 action client
+source <ros2-install-dir>/setup.bash
+ros2 run action_tutorials_cpp fibonacci_action_client 20
+```
+
+For sending goals from ROS1 action client to ROS2 action server
+```
+# Terminal 1 -- action bridge
+# Make sure roscore is already running
+source <ros1_bridge-install-dir>/setup.bash
+ros2 run ros1_bridge action_bridge ros2 action_tutorials_interfaces action/Fibonacci fibonacci
+
+# Terminal 2 -- ROS2 action server
+source <ros2-install-dir>/setup.bash
+ros2 run action_tutorials_cpp fibonacci_action_server
+
+# Terminal 3 -- ROS1 action client
+source <ros1-install-dir>/setup.bash
+rosrun actionlib_tutorials fibonacci_client 20
+```
+
+`dynamic_bridge` has been extended to handle actions as well.