<gazebo_ros> tag in ROS plugin un-supported

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I follow the ROS plugin here. And when I catkin_make, the error outputs is:

Invalid package manifest "/home/winston/catkinws/src/gazeborosplugin/package.xml": Error(s) in /home/winston/catkinws/src/gazeborosplugin/package.xml: - The manifest (with format version 1) must not contain the following tags: gazebo_ros

So the problem is the <gazebo_ros> tag in the package.xml file. This is my package.xml file:

<?xml version="1.0"?>
<package>
  <name>gazebo_ros_plugin</name>
  <version>0.0.0</version>
  <description>The gazebo_ros_plugin package</description>
  <maintainer email="winston@todo.todo">winston</maintainer>
  <license>TODO</license>

  <buildtool_depend>catkin</buildtool_depend>
  <build_depend>gazebo_ros</build_depend>
  <build_depend>roscpp</build_depend>
  <run_depend>gazebo_ros</run_depend>
  <run_depend>roscpp</run_depend>

  <gazebo_ros plugin_path="${prefix}/lib" gazebo_media_path="${prefix}" />

  <export>
   </export>
</package>

However, if I put the <gazebo_ros> tag inside <export> tag, this error disappears but new errors occur:

In file included from /home/winston/catkinws/src/gazeborosplugin/src/simpleworldplugin.cpp:1:0: /usr/include/gazebo-5.0/gazebo/common/Plugin.hh:367:3: error: expected ‘}’ at end of input } ^ /home/winston/catkinws/src/gazeborosplugin/src/simpleworldplugin.cpp:26:1: note: in expansion of macro ‘GZREGISTERWORLDPLUGIN’ GZREGISTERWORLDPLUGIN(WorldPluginTutorial) ^

Any suggestions?