fix

jambotron-ui/src/app/modules/admin-module/admin.module.ts

@@ -2,12 +2,21 @@ import {CUSTOM_ELEMENTS_SCHEMA, NgModule} from '@angular/core';
 import {RouterModule} from '@angular/router';
 import {AdminComponent} from './admin.component/admin.component';
 import {adminRouting} from './admin.routing';
+import {MatTreeModule} from '@angular/material/tree';
+import {MatIconModule} from '@angular/material/icon';
+import {MatButtonModule} from '@angular/material/button';
+import {MatProgressSpinnerModule} from '@angular/material/progress-spinner';
 
 @NgModule({
   declarations: [
 
   ],
-  imports: [adminRouting, AdminComponent],
+  imports: [adminRouting, AdminComponent,
+    MatTreeModule,
+    MatIconModule,
+    MatButtonModule,
+    MatProgressSpinnerModule
+  ],
   exports: [RouterModule],
   schemas:[CUSTOM_ELEMENTS_SCHEMA]
 })