Clarified comments

ref #90

src/models/actions/update/UpdateDistanceDonation.ts

@@ -11,7 +11,7 @@ import { UpdateDonation } from './UpdateDonation';
 export class UpdateDistanceDonation extends UpdateDonation {
 
     /**
-     * The donation's associated runner.
+     * The donation's associated runner's id.
      * This is important to link the runner's distance ran to the donation.
      */
     @IsInt()

src/models/actions/update/UpdateDonation.ts

@@ -16,7 +16,7 @@ export abstract class UpdateDonation {
     id: number;
 
     /**
-     * The updated donation's associated donor.
+     * The updated donation's associated donor's id.
      * This is important to link donations to donors.
      */
     @IsInt()