add start at ipt as sort criterion

src/app/components/cards/cards.component.ts

@@ -52,6 +52,7 @@ export class CardsComponent {
     { value: CardSort.Duplicates, viewValue: 'Anzahl Dubletten' },
     { value: CardSort.Acronym, viewValue: 'Kürzel' },
     { value: CardSort.Name, viewValue: 'Name' },
+    { value: CardSort.Start, viewValue: 'Start bei ipt' },
   ];
 
   constructor(private readonly store: Store) {

src/app/models/card-sort.enum.ts

@@ -3,4 +3,5 @@ export enum CardSort {
   Duplicates = 'duplicates',
   Acronym = 'acronym',
   Name = 'name',
+  Start = 'start',
 }

src/app/state/card/card.selectors.ts

@@ -91,6 +91,8 @@ export const selectCardsSorted = createSelector(
           if (!a.last_received) return 1;
           if (!b.last_received) return -1;
           return b.last_received.localeCompare(a.last_received);
+        case CardSort.Start:
+          return b.start_at_ipt.localeCompare(a.start_at_ipt);
         default:
           return 0;
       }