code: public UNode toDoc() {
          UNode userNode = UNode.createMapNode(m_userID, "user");
          if (!Utils.isEmpty(m_password)) {
              userNode.addValueNode("password", m_password, true);
          }
          if (!Utils.isEmpty(m_hash)) {
              userNode.addValueNode("hash", m_hash, true);
          }
          String permissions = "ALL";
          if (m_permissions.size() > 0) {
              permissions = Utils.concatenate(m_permissions, ",");
          }
          userNode.addValueNode("permissions", permissions);
          return userNode;
      }
docs: Serialize this user definition into a UNode tree.
  
  @return  Root {@link UNode} of the serialized tree.