plug in is not working?

[Alvin1701]

Hi all,

im trying to use this plug in with my differential drive robot. im using ROS melodic and gazebo9. i follow the steps given by adding dc_motor macro in a descriptor file as if it were a joint. When i launch the model in gazebo everything looks fine. However, when i use rostopic list in the terminal, the topic is not published. i was wondering whether i am using it wrong (i'm a newbie at this) or what. so any kind of help is appreciated. thanks!

link for my code : https://github.com/Alvin1701/Mobile-robot-motor-plugin.git