Added a file with an example to apply a wrench to the robot.

bioloid_controller_cm510/apply_wrench.txt

+rosservice call /gazebo/apply_body_wrench '{body_name: "bioloid::base_link", reference_frame: "bioloid::base_link", wrench: { force: { x: 0, y: 500.0, z: 0.0 } }, start_time: 0, duration: 1000000 }'