Before starting development with Gazebo plugins, we have to install the dependent packages. This is because we are working with ROS Kinetic which has Gazebo version 7.x by default. Therefore, we have to install Gazebo's development package, libgazebo7-dev:
$sudo apt-get install libgazebo7-dev
The Gazebo plugins are independent of ROS and we don't need the ROS libraries to build the plugin.