Wrap the room creation form into a form element

src/app/room-creation/room-creation.component.html

+<form>
 <div fxLayout="column" fxLayoutAlign="center" fxLayoutGap="10px">
   <mat-form-field>
     <input matInput #longRoomName class="input-block" type="text" placeholder="Name" maxlength="50"
@@ -21,3 +22,4 @@
   <button mat-raised-button color="primary" (click)="addRoom(longRoomName.value, shortRoomName.value)">Create room
   </button>
 </div>
+</form>