def addon name,version=@@latest_version
            config = get_config(self._version)
            addon_author,addon_name = name.split("/")
            if File.exists?("#{config["dirname"]}/addons/#{addon_name}")
                puts "update #{name}"
                `cd #{config["dirname"]}/addons/#{addon_name} && git pull` 
            else
                puts "clone #{name}"
                `cd #{config["dirname"]}/addons && git clone https://github.com/#{name}.git` 
            end
        end
def addon name,version=@@latest_version
            config = get_config(self._version)
            addon_author,addon_name = name.split("/")
            if File.exists?("#{config["dirname"]}/addons/#{addon_name}")
                puts "update #{name}"
                `cd #{config["dirname"]}/addons/#{addon_name} && git pull` 
            else
                puts "clone #{name}"
                `cd #{config["dirname"]}/addons && git clone https://github.com/#{name}.git` 
            end
        end
install or update the addon