ERROR in srcappapp.module.ts(87,5): Error during template compile of 'AppModule'

  Could not resolve ag-grid-angular relative to c:/workspace/.../Angular/src/app/app.module.ts..

src/app.../status-cellrenderer.component.ts(2,37): error TS2307: Cannot find module 'ag-grid-angular'.

src/app/app.module.ts(36,30): error TS2307: Cannot find module 'ag-grid-angular'.