Create cobra command

cmd/pageship/app/generate.go

@@ -0,0 +1,31 @@
+package app
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+)
+
+func init() {
+	rootCmd.AddCommand(generateCmd)
+	generateCmd.AddCommand(generateDockerfileCmd)
+}
+
+var generateCmd = &cobra.Command{
+	Use:   "generate [command]",
+	Short: "Generate files",
+	Args:  cobra.NoArgs, //if unknown command, will return error just like main pageship command
+	RunE: func(cmd *cobra.Command, args []string) error {
+		cmd.Help() //show help if no subcommand supplied
+		return nil
+	},
+}
+
+var generateDockerfileCmd = &cobra.Command{
+	Use:   "dockerfile",
+	Short: "Generate dockerfile",
+	RunE: func(cmd *cobra.Command, args []string) error {
+		fmt.Println("buh")
+		return nil
+	},
+}