Bug fixing

src/myaktion/db/db.go

src/myaktion/go.mod

src/myaktion/handler/campaign.go

src/myaktion/handler/campaign_test.go

src/myaktion/handler/donation.go

src/myaktion/handler/health_test.go

src/myaktion/main.go

src/myaktion/service/campaign.go

src/myaktion/service/donation.go