How to add the installed application to the application menu

Here we will install the Lumaqq in the directory /home/wason/tools and we will add a shortcut for the application menu of the category internet
In the first place, build a new desktop file for lumaqq
sudo emacs /usr/share/applications/LumaQQ.desktop

然后，在新增的文件内加入下面这几行
[Desktop Entry]
Name=LumaQQ
Comment=QQ Client
Exec=/home/wason/tools/LumaQQ/lumaqq
Icon=/home/wason/tools/LumaQQ/QQ.png
Terminal=false
Type=Application
Categories=Application;Network;

the Categories is independant which one you want to added, we could find corresponding catergory by look up exiested file in /usr/share/applications/