fixed bug. change Collection.collection to Model.collection

backbone/backbone-tests.ts

@@ -140,6 +140,14 @@ function test_collection() {
     var alphabetical = books.sortBy((book: Book): number => {
         return null;
     });
+
+    var model: Book = new Book({title: "Test", author: "Mike"});
+    books.add(model);
+    var model2: Book = model.collection.first();
+    if (model !== model2) {
+        throw new Error("Error");
+    }
+
 }
 
 //////////

backbone/backbone.d.ts

@@ -95,6 +95,8 @@ declare module Backbone {
         attributes: any;
         changed: any[];
         cid: string;
+        collection: Collection<any>;
+
         /**
         * Default attributes for the model. It can be an object hash or a method returning an object hash.
         * For assigning an object hash, do it like this: this.defaults = <any>{ attribute: value, ... };
@@ -156,7 +158,6 @@ declare module Backbone {
         //model: typeof TModel;
         model: { new(): TModel; }; // workaround
         models: TModel[];
-        collection: TModel;
         length: number;
 
         constructor(models?: TModel[], options?: any);