title: ngbDatepicker of ng-bootstrap is not working
body: <p>I followed the solution mentioned <a href="https://stackoverflow.com/questions/47247853/ng-bootstrap-datepicker-not-working">here</a> still I am getting the exception</p>
  
  <pre><code>Uncaught Error: Template parse errors:
  There is no directive with "exportAs" set to "ngbDatepicker" ("   &lt;input class="form-control" placeholder="yyyy-mm-dd" name="dp" [(ngModel)]="model" ngbDatepicker [ERROR -&gt;]#d="ngbDatepicker"&gt;
            &lt;div class="input-group-append"&gt;
           &lt;button class="btn btn-out"): ng:///LayoutModule/StudentComponent.html@34:107
  Can't bind to 'ngModel' since it isn't a known property of 'input'. ("    &lt;div class="col-sm-3"&gt;
           &lt;input class="form-control" placeholder="yyyy-mm-dd" name="dp" [ERROR -&gt;][(ngModel)]="model" ngbDatepicker #d="ngbDatepicker"&gt;
           &lt;div class="input-group-append"&gt;
  "): ng:///LayoutModule/StudentComponent.html@34:73
  at syntaxError (compiler.js:215)
  at TemplateParser.push../node_modules/@angular/compiler/fesm5/compiler.js.TemplateParser.parse (compiler.js:14705)
  </code></pre>
  
  <p>My app.module.ts</p>
  
  <pre><code>    import { BrowserModule } from '@angular/platform-browser';
      import { NgModule, Injectable } from '@angular/core';
      import { FormsModule } from '@angular/forms';
      import { Router, Routes, RouterModule, CanActivateChild, 
      ActivatedRouteSnapshot, RouterStateSnapshot } from "@angular/router";
      import { Observable } from 'rxjs';
      import { NgbModal, NgbModule } from '@ng-bootstrap/ng-bootstrap';
  
      @NgModule({
      imports: [   
      BrowserModule,
      HttpClientModule,
      HeaderModule,
      LayoutModule,
      FormsModule  ,
      NgbModule.forRoot(),
      RouterModule.forRoot(routes, {useHash: true}),  
    ],
    declarations: [///declare components here]
   })
  </code></pre>
  
  <p>html</p>
  
  <pre><code>&lt;div class="col-sm-1"&gt;
        &lt;label for="dob"&gt;DOB&lt;/label&gt;
      &lt;/div&gt;
      &lt;div class="col-sm-3"&gt;
        &lt;input class="form-control" placeholder="yyyy-mm-dd" name="dp" [(ngModel)]="model" ngbDatepicker #d="ngbDatepicker"&gt;
        &lt;div class="input-group-append"&gt;
          &lt;button class="btn btn-outline-secondary" (click)="d.toggle()" type="button"&gt;
            &lt;img src="img/calendar-icon.svg" style="width: 1.2rem; height: 1rem; cursor: pointer;" /&gt;
          &lt;/button&gt;
        &lt;/div&gt;
      &lt;/div&gt;
  </code></pre>