code: function injectModel(name, config, m) {
      const modelConfig = app.think.config('model', undefined, m);
      const cacheConfig = app.think.config('cache', undefined, m);
      config = helper.parseAdapterConfig(modelConfig, config);
      const instance = model(name, config, m);
      instance._cacheConfig = cacheConfig;
      return instance;
    }
docs: inject model method
  @param {String} name
  @param {Object} config
  @param {String} m