VDB-919 Generalise converter (#152)

* Generalise transformer stack to use InsertionModel

* Add tests for event repository

* Restrict accepted values in InsertionModel

* Add call to repository.SetDB

* Improve error propagation/clarity on GetABI()

* Remove maker references in example

* Please golint

* refactor rollback error handling in repository

* Cleaner errors in repository, refactor tests

integration_test/integration_test_suite_test.go

@@ -17,6 +17,8 @@
 package integration_test
 
 import (
+	"github.com/sirupsen/logrus"
+	"io/ioutil"
 	"testing"
 
 	. "github.com/onsi/ginkgo"
@@ -27,3 +29,7 @@ func TestIntegrationTest(t *testing.T) {
 	RegisterFailHandler(Fail)
 	RunSpecs(t, "IntegrationTest Suite")
 }
+
+var _ = BeforeSuite(func() {
+	logrus.SetOutput(ioutil.Discard)
+})