Refactoring: switched update runner group from objects to ids

ref #90

src/models/actions/update/UpdateRunner.ts

@@ -1,4 +1,4 @@
-import { IsInt, IsObject } from 'class-validator';
+import { IsInt, IsPositive } from 'class-validator';
 import { getConnectionManager } from 'typeorm';
 import { RunnerGroupNotFoundError } from '../../../errors/RunnerGroupErrors';
 import { RunnerOrganisationWrongTypeError } from '../../../errors/RunnerOrganisationErrors';
@@ -20,11 +20,11 @@ export class UpdateRunner extends CreateParticipant {
     id: number;
 
     /**
-     * The updated runner's new team/org.
-     * Just has to contain the group's id -everything else won't be checked or changed.
+     * The updated runner's group's id.
      */
-    @IsObject()
-    group: RunnerGroup;
+    @IsInt()
+    @IsPositive()
+    group: number;
 
     /**
      * Updates a provided Runner entity based on this.