registerAdapter (name, adapter, opts) {
    opts || (opts = {})
    this.getAdapters()[name] = adapter
    // Optionally make it the default adapter for the target.
    if (opts === true || opts.default) {
      this.defaultAdapter = name
    }
  }
Register an adapter on this Mapper under the given name.

@method Mapper#registerAdapter
@param {string} name The name of the adapter to register.
@param {Adapter} adapter The adapter to register.
@param {object} [opts] Configuration options.
@param {boolean} [opts.default=false] Whether to make the adapter the
default adapter for this Mapper.
@since 3.0.0
@tutorial ["http://www.js-data.io/v3.0/docs/connecting-to-a-data-source","Connecting to a data source"]