feat: config/users import/export (#613)

Supports json and yaml.

cmd/users_export.go

@@ -0,0 +1,22 @@
+package cmd
+
+import (
+	"github.com/spf13/cobra"
+)
+
+func init() {
+	usersCmd.AddCommand(usersExportCmd)
+}
+
+var usersExportCmd = &cobra.Command{
+	Use:   "export <filename>",
+	Short: "Export all users.",
+	Args:  jsonYamlArg,
+	Run: python(func(cmd *cobra.Command, args []string, d pythonData) {
+		list, err := d.store.Users.Gets("")
+		checkErr(err)
+
+		err = marshal(args[0], list)
+		checkErr(err)
+	}, pythonConfig{}),
+}