code: func (h *Handler) servePutRaftPeer(w http.ResponseWriter, r *http.Request, params httprouter.Params) {
  	peer := params.ByName("peer")
  	if err := h.Store.AddPeer(peer); err == ErrNotLeader {
  		h.redirectToLeader(w, r)
  		return
  	} else if err != nil {
  		hh.Error(w, err)
  		return
  	}
  	var targetLogIndex dt.TargetLogIndex
  	targetLogIndex.LastIndex = h.Store.LastIndex()
  	hh.JSON(w, 200, targetLogIndex)
  }
docs: // servePutRaftNodes joins a peer to the store cluster.