feat:#6 added tests with db for unused feed delete

backend/service/functions/time/mockClock.go

@@ -0,0 +1,10 @@
+package time
+
+import "time"
+
+type MockClock struct {
+	NowTime time.Time
+}
+
+func (m MockClock) Now() time.Time                       { return m.NowTime }
+func (MockClock) After(d time.Duration) <-chan time.Time { return time.After(d) }