Append API links

app/Api/V1/Controllers/Models/ObjectGroup/DestroyController.php

@@ -57,6 +57,9 @@ class DestroyController extends Controller
     }
 
     /**
+     * This endpoint is documented at:
+     * https://api-docs.firefly-iii.org/#/object_groups/deleteObjectGroup
+     *
      * Remove the specified resource from storage.
      *
      * @param ObjectGroup $objectGroup

app/Api/V1/Controllers/Models/ObjectGroup/ListController.php

@@ -63,7 +63,10 @@ class ListController extends Controller
     }
 
     /**
-     * List all bills
+     * This endpoint is documented at:
+     * https://api-docs.firefly-iii.org/#/object_groups/listBillByObjectGroup
+     *
+     * List all bills in this object group
      *
      * @param ObjectGroup $objectGroup
      *
@@ -96,6 +99,9 @@ class ListController extends Controller
     }
 
     /**
+     * This endpoint is documented at:
+     * https://api-docs.firefly-iii.org/#/object_groups/listPiggyBankByObjectGroup
+     *
      * List all piggies under the object group.
      *
      * @param ObjectGroup $objectGroup

app/Api/V1/Controllers/Models/ObjectGroup/ShowController.php

@@ -64,6 +64,9 @@ class ShowController extends Controller
     }
 
     /**
+     * This endpoint is documented at:
+     * https://api-docs.firefly-iii.org/#/object_groups/listObjectGroups
+     *
      * Display a listing of the resource.
      *
      * @param Request $request
@@ -99,6 +102,9 @@ class ShowController extends Controller
     }
 
     /**
+     * This endpoint is documented at:
+     * https://api-docs.firefly-iii.org/#/object_groups/getObjectGroup
+     *
      * Show single instance.
      *
      * @param ObjectGroup $objectGroup

app/Api/V1/Controllers/Models/ObjectGroup/UpdateController.php

@@ -60,6 +60,9 @@ class UpdateController extends Controller
     }
 
     /**
+     * This endpoint is documented at:
+     * https://api-docs.firefly-iii.org/#/object_groups/updateObjectGroup
+     *
      * @param UpdateRequest $request
      * @param ObjectGroup   $objectGroup
      *