code: func (api UsersAPI) GetUserRegistryEntry(w http.ResponseWriter, r *http.Request) {
  	username := mux.Vars(r)["username"]
  	key := mux.Vars(r)["key"]
  
  	mgr := registry.NewManager(r)
  	registryEntry, err := mgr.GetRegistryEntry(username, "", key)
  	if err != nil {
  		log.Error(err.Error())
  		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
  		return
  	}
  	if registryEntry == nil {
  		http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
  		return
  	}
  	w.Header().Set("Content-Type", "application/json")
  	json.NewEncoder(w).Encode(registryEntry)
  }
docs: // GetUserRegistryEntry is the handler for GET /users/{username}/registry/{key}
  // Get a RegistryEntry from the user's registry.