我有一个自定义用户、角色和角色Map，名为adminuser、adminrole和adminrolemapping。我已经用数据填充了数据库，我正在使用mysql和loopback3.19。我的型号配置是：

{
  "name": "AdminRole",
  "plural": "adminRoles",
   ...
  "base": "Role",
  "relations": {
    "users": {
      "type": "hasMany",
      "model": "AdminUser",
      "foreignKey": "principalId",
      "through": "AdminRoleMapping"
    }
  },
...
}

{
  "name": "AdminUser",
  "plural": "adminUsers",
  "base": "User",
   ...
    "roles": {
      "type": "hasMany",
      "model": "AdminRole",
      "foreignKey": "principalId",
      "through": "AdminRoleMapping"
    }
  },
  ...
}

{
  "name": "AdminRoleMapping",
  "description": "Map principals to roles",
  "plural": "adminRoleMappings",
  "base": "RoleMapping",
  ....
  "relations": {
    "principal": {
      "type": "belongsTo",
      "model": "AdminUser",
      "foreignKey": "principalId"
    },
    "roles": {
      "type": "belongsTo",
      "model": "AdminRole",
      "foreignKey": "roleId"
    }
  },
  ....
}

当我尝试访问 GET /adminUsers/{id}/roles 然后我得到状态错误500 "message": "Relation \"adminRole\" is not defined for AdminRoleMapping model" 我的设置有什么问题？我已经看过医生了。