Feature mongo gen (#546)

* add feature: mongo code generation

* upgrade version

* update doc

* format code

* update update.tpl of mysql

tools/goctl/model/mongo/mongo.go

@@ -0,0 +1,39 @@
+package mongo
+
+import (
+	"errors"
+	"path/filepath"
+	"strings"
+
+	"github.com/tal-tech/go-zero/tools/goctl/config"
+	"github.com/tal-tech/go-zero/tools/goctl/model/mongo/generate"
+	"github.com/urfave/cli"
+)
+
+// Command provides the entry for goctl
+func Action(ctx *cli.Context) error {
+	tp := ctx.StringSlice("type")
+	c := ctx.Bool("cache")
+	o := strings.TrimSpace(ctx.String("dir"))
+	s := ctx.String("style")
+	if len(tp) == 0 {
+		return errors.New("missing type")
+	}
+
+	cfg, err := config.NewConfig(s)
+	if err != nil {
+		return err
+	}
+
+	a, err := filepath.Abs(o)
+	if err != nil {
+		return err
+	}
+
+	return generate.Do(&generate.Context{
+		Types:  tp,
+		Cache:  c,
+		Output: a,
+		Cfg:    cfg,
+	})
+}