Feature mongo gen (#546)

* add feature: mongo code generation

* upgrade version

* update doc

* format code

* update update.tpl of mysql

tools/goctl/model/mongo/generate/template.go

@@ -0,0 +1,50 @@
+package generate
+
+import (
+	"fmt"
+
+	"github.com/tal-tech/go-zero/tools/goctl/model/mongo/template"
+	"github.com/tal-tech/go-zero/tools/goctl/util"
+	"github.com/urfave/cli"
+)
+
+const (
+	category          = "mongo"
+	modelTemplateFile = "model.tpl"
+	errTemplateFile   = "err.tpl"
+)
+
+var templates = map[string]string{
+	modelTemplateFile: template.Text,
+	errTemplateFile:   template.Error,
+}
+
+func Category() string {
+	return category
+}
+
+func Clean() error {
+	return util.Clean(category)
+}
+
+func Templates(_ *cli.Context) error {
+	return util.InitTemplates(category, templates)
+}
+
+func RevertTemplate(name string) error {
+	content, ok := templates[name]
+	if !ok {
+		return fmt.Errorf("%s: no such file name", name)
+	}
+
+	return util.CreateTemplate(category, name, content)
+}
+
+func Update() error {
+	err := Clean()
+	if err != nil {
+		return err
+	}
+
+	return util.InitTemplates(category, templates)
+}