message: Add createDirectory to Document
diff: @@ -10,7 +10,7 @@ import { Container, Loader } from "@microsoft/fluid-container-loader";
  import { IContainerRuntimeOptions } from "@microsoft/fluid-container-runtime";
  import { Deferred } from "@microsoft/fluid-core-utils";
  import * as ink from "@microsoft/fluid-ink";
  -import { ISharedMap, SharedMap } from "@microsoft/fluid-map";
  +import { ISharedDirectory, ISharedMap, SharedDirectory, SharedMap } from "@microsoft/fluid-map";
  import {
  IDocumentMessage,
  IDocumentServiceFactory,
  @@ -132,6 +132,13 @@ export class Document extends EventEmitter {
  return SharedMap.create(this.runtime);
  }
  + /**
  + * Creates a new shared directory
  + */
  + public createDirectory(): ISharedDirectory {
  + return SharedDirectory.create(this.runtime);
  + }
  +
  /**
  * Creates a new shared cell.
  */
  