grails3 URLMapping加前缀（如：/api/）

package resttutorial

class UrlMappings {

    static mappings = {
      group("/api") {
        delete "/$controller/$id(.$format)?"(action:"delete")
        get "/$controller(.$format)?"(action:"index")
        get "/$controller/$id(.$format)?"(action:"show")
        post "/$controller(.$format)?"(action:"save")
        put "/$controller/$id(.$format)?"(action:"update")
        patch "/$controller/$id(.$format)?"(action:"patch")
      }
        ...
    }
}