fix(rating): added support of reactive forms

fixes #298

src/rating/rating.component.ts

@@ -1,11 +1,15 @@
-import {
-  Component, EventEmitter, HostListener, Input, OnInit, Output, Self
-} from '@angular/core';
-import { ControlValueAccessor, NgModel } from '@angular/forms';
+import { Component, EventEmitter, HostListener, Input, OnInit, Output, forwardRef } from '@angular/core';
+import { ControlValueAccessor, NG_VALUE_ACCESSOR } from '@angular/forms';
 
 /* tslint:disable-next-line */
 const KeyboardEvent = (global as any).KeyboardEvent as KeyboardEvent;
 
+export const RATING_CONTROL_VALUE_ACCESSOR: any = {
+  provide: NG_VALUE_ACCESSOR,
+  useExisting: forwardRef(() => RatingComponent),
+  multi: true
+};
+
 @Component({
   /* tslint:disable */
   selector: 'rating[ngModel]',
@@ -18,29 +22,28 @@ const KeyboardEvent = (global as any).KeyboardEvent as KeyboardEvent;
       </template>
     </span>
   `,
-  providers: [NgModel]
+  providers: [RATING_CONTROL_VALUE_ACCESSOR]
 })
 export class RatingComponent implements ControlValueAccessor, OnInit {
-  @Input() public max:number;
-  @Input() public stateOn:string;
-  @Input() public stateOff:string;
-  @Input() public readonly:boolean;
-  @Input() public titles:string[];
-  @Input() public ratingStates:{stateOn:string, stateOff:string}[];
+  @Input() public max: number;
+  @Input() public stateOn: string;
+  @Input() public stateOff: string;
+  @Input() public readonly: boolean;
+  @Input() public titles: string[];
+  @Input() public ratingStates: {stateOn: string, stateOff: string}[];
 
-  @Output() public onHover:EventEmitter<number> = new EventEmitter<number>(false);
-  @Output() public onLeave:EventEmitter<number> = new EventEmitter<number>(false);
+  @Output() public onHover: EventEmitter<number> = new EventEmitter<number>(false);
+  @Output() public onLeave: EventEmitter<number> = new EventEmitter<number>(false);
 
-  public onChange:any = Function.prototype;
-  public onTouched:any = Function.prototype;
+  public onChange: any = Function.prototype;
+  public onTouched: any = Function.prototype;
 
-  public cd:NgModel;
-  public range:any[];
-  public value:number;
-  protected preValue:number;
+  public range: any[];
+  public value: number;
+  protected preValue: number;
 
   @HostListener('keydown', ['$event'])
-  public onKeydown(event:KeyboardEvent):void {
+  public onKeydown(event: KeyboardEvent): void {
     if ([37, 38, 39, 40].indexOf(event.which) === -1) {
       return;
     }
@@ -51,12 +54,7 @@ export class RatingComponent implements ControlValueAccessor, OnInit {
     this.rate(this.value + sign);
   }
 
-  public constructor(@Self() cd:NgModel) {
-    this.cd = cd;
-    cd.valueAccessor = this;
-  }
-
-  public ngOnInit():void {
+  public ngOnInit(): void {
     this.max = typeof this.max !== 'undefined' ? this.max : 5;
     this.readonly = this.readonly === true;
     this.stateOn = typeof this.stateOn !== 'undefined'
@@ -72,7 +70,7 @@ export class RatingComponent implements ControlValueAccessor, OnInit {
   }
 
   // model -> view
-  public writeValue(value:number):void {
+  public writeValue(value: number): void {
     if (value % 1 !== value) {
       this.value = Math.round(value);
       this.preValue = value;
@@ -83,37 +81,37 @@ export class RatingComponent implements ControlValueAccessor, OnInit {
     this.value = value;
   }
 
-  public enter(value:number):void {
+  public enter(value: number): void {
     if (!this.readonly) {
       this.value = value;
       this.onHover.emit(value);
     }
   }
 
-  public reset():void {
+  public reset(): void {
     this.value = this.preValue;
     this.onLeave.emit(this.value);
   }
 
-  public registerOnChange(fn:(_:any) => {}):void {
+  public registerOnChange(fn: (_: any) => {}): void {
     this.onChange = fn;
   }
 
-  public registerOnTouched(fn:() => {}):void {
+  public registerOnTouched(fn: () => {}): void {
     this.onTouched = fn;
   }
 
-  public rate(value:number):void {
+  public rate(value: number): void {
     if (!this.readonly && value >= 0 && value <= this.range.length) {
       this.writeValue(value);
-      this.cd.viewToModelUpdate(value);
+      this.onChange(value);
     }
   }
 
-  protected buildTemplateObjects(ratingStates:any[], max:number):any[] {
+  protected buildTemplateObjects(ratingStates: any[], max: number): any[] {
     ratingStates = ratingStates || [];
     let count = ratingStates.length || max;
-    let result:any[] = [];
+    let result: any[] = [];
     for (let i = 0; i < count; i++) {
       result.push(Object.assign({
         index: i,