Use vendor when building (#201)

* Use vendor code for all go calls

* Add missing vendor dependencies

* Add travis_retry to yarn install

* Fix go test call

vendor/github.com/99designs/gqlgen/codegen/util.go

@@ -0,0 +1,47 @@
+package codegen
+
+import (
+	"go/types"
+	"strings"
+
+	"github.com/pkg/errors"
+)
+
+func findGoNamedType(def types.Type) (*types.Named, error) {
+	if def == nil {
+		return nil, nil
+	}
+
+	namedType, ok := def.(*types.Named)
+	if !ok {
+		return nil, errors.Errorf("expected %s to be a named type, instead found %T\n", def.String(), def)
+	}
+
+	return namedType, nil
+}
+
+func findGoInterface(def types.Type) (*types.Interface, error) {
+	if def == nil {
+		return nil, nil
+	}
+	namedType, err := findGoNamedType(def)
+	if err != nil {
+		return nil, err
+	}
+	if namedType == nil {
+		return nil, nil
+	}
+
+	underlying, ok := namedType.Underlying().(*types.Interface)
+	if !ok {
+		return nil, errors.Errorf("expected %s to be a named interface, instead found %s", def.String(), namedType.String())
+	}
+
+	return underlying, nil
+}
+
+func equalFieldName(source, target string) bool {
+	source = strings.Replace(source, "_", "", -1)
+	target = strings.Replace(target, "_", "", -1)
+	return strings.EqualFold(source, target)
+}