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/plugin/resolvergen/resolver.go

@@ -0,0 +1,53 @@
+package resolvergen
+
+import (
+	"log"
+	"os"
+
+	"github.com/99designs/gqlgen/codegen"
+	"github.com/99designs/gqlgen/codegen/templates"
+	"github.com/99designs/gqlgen/plugin"
+	"github.com/pkg/errors"
+)
+
+func New() plugin.Plugin {
+	return &Plugin{}
+}
+
+type Plugin struct{}
+
+var _ plugin.CodeGenerator = &Plugin{}
+
+func (m *Plugin) Name() string {
+	return "resovlergen"
+}
+func (m *Plugin) GenerateCode(data *codegen.Data) error {
+	if !data.Config.Resolver.IsDefined() {
+		return nil
+	}
+
+	resolverBuild := &ResolverBuild{
+		Data:         data,
+		PackageName:  data.Config.Resolver.Package,
+		ResolverType: data.Config.Resolver.Type,
+	}
+	filename := data.Config.Resolver.Filename
+
+	if _, err := os.Stat(filename); os.IsNotExist(errors.Cause(err)) {
+		return templates.Render(templates.Options{
+			PackageName: data.Config.Resolver.Package,
+			Filename:    data.Config.Resolver.Filename,
+			Data:        resolverBuild,
+		})
+	}
+
+	log.Printf("Skipped resolver: %s already exists\n", filename)
+	return nil
+}
+
+type ResolverBuild struct {
+	*codegen.Data
+
+	PackageName  string
+	ResolverType string
+}