title: how to use nb-select & nb-option
body: <p>'nb-option' is not a known element:
  1. If 'nb-option' is an Angular component, then verify that it is part of this module.
  2. If 'nb-option' is a Web Component then add 'CUSTOM_ELEMENTS_SCHEMA' to the '@NgModule.schemas' of this component to suppress this message.</p>
  
  <p><strong>component.html</strong></p>
  
  <pre><code>&lt;nb-card-body&gt;
    &lt;nb-select placeholder="10" [(ngModel)]="defaultRowPerPage"&gt;
      &lt;nb-option (click)="setPager()" value="10"&gt;10&lt;/nb-option&gt;
      &lt;nb-option (click)="setPager()" value="20"&gt;20&lt;/nb-option&gt;
      &lt;nb-option (click)="setPager()" value="50"&gt;50&lt;/nb-option&gt;
      &lt;nb-option (click)="setPager()" value="100"&gt;100&lt;/nb-option&gt;
    &lt;/nb-select&gt;
  &lt;ng2-smart-table [settings]="settings" [source]="source" &gt;
  &lt;/ng2-smart-table&gt;
  &lt;/nb-card-body&gt;
  </code></pre>
  
  <p><strong>module.ts</strong></p>
  
  <pre><code>const NB_MODULES = [
    NbCardModule,
    NbLayoutModule,
    NbTabsetModule,
    NbRouteTabsetModule,
    NbMenuModule,
    NbUserModule,
    NbActionsModule,
    NbSearchModule,
    NbSidebarModule,
    NbCheckboxModule,
    NbPopoverModule,
    NbContextMenuModule,
    NgbModule,
    NbSecurityModule,
  ];
  </code></pre>