feat: replace --operation flag by backup and restore command

cmd/history.go

@@ -0,0 +1,14 @@
+package cmd
+
+import (
+	"github.com/jkaninda/pg-bkup/utils"
+	"github.com/spf13/cobra"
+)
+
+var HistoryCmd = &cobra.Command{
+	Use:   "history",
+	Short: "Show the history of backup",
+	Run: func(cmd *cobra.Command, args []string) {
+		utils.ShowHistory()
+	},
+}