Add missing ripple.

frontend/src/app/pages/my-publications/my-publications.component.html

@@ -4,6 +4,7 @@
     class="new-publication"
     matTooltip="Add a new publication"
     matTooltipPosition="left"
+    matRipple
     i18n-matTooltip>
     +
 </a>

frontend/src/app/pages/my-publications/my-publications.component.ts

@@ -7,6 +7,7 @@ import { Publication } from "../../core/rest-services/publications/model/publica
 import { CommonModule } from "@angular/common";
 import { RouterModule } from "@angular/router";
 import { MatTooltipModule } from "@angular/material/tooltip";
+import { MatRippleModule } from "@angular/material/core";
 
 
 @Component({
@@ -17,8 +18,9 @@ import { MatTooltipModule } from "@angular/material/tooltip";
     imports: [
         CommonModule,
         MatProgressSpinnerModule,
-        PublicationListComponent,
+        MatRippleModule,
         MatTooltipModule,
+        PublicationListComponent,
         RouterModule
     ],
     providers: [MyPublicationsService]