Implmented cascading donation deletion for runners and donors

ref #66

src/errors/RunnerErrors.ts

@@ -33,4 +33,15 @@ export class RunnerGroupNeededError extends NotAcceptableError {
 
 	@IsString()
 	message = "Runner's need to be part of one group (team or organisation)! \n You provided neither."
+}
+
+/**
+* Error to throw when a runner still has distance donations associated.
+*/
+export class RunnerHasDistanceDonationsError extends NotAcceptableError {
+	@IsString()
+	name = "RunnerHasDistanceDonationsError"
+
+	@IsString()
+	message = "This runner still has distance donations associated with it. \n If you want to delete this runner with all it's donations and teams add `?force` to your query."
 }