如何从Rails中的枚举值获取键名？

class User < ApplicationRecord
  enum role: { admin: 0, moderator: 1, user: 2 }
end

roles = User.roles
# => { "admin" => 0, "moderator" => 1, "user" => 2 }

inverted_roles = roles.invert
# => { 0 => "admin", 1 => "moderator", 2 => "user" }

role_name = inverted_roles.fetch(1) # 通过fetch方法获取
# => "moderator"

role_name = inverted_roles[1] # 直接通过索引获取
# => "moderator"