RuCaptcha.configure do
  # Color style, default: :colorful, allows: [:colorful, :black_white]
  # self.style = :colorful
  # Custom captcha code expire time if you need, default: 2 minutes
  self.expires_in = 60.minutes
  # [Requirement / 重要]
  # Store Captcha code where, this config more like Rails config.cache_store
  # default: Read config info from `Rails.application.config.cache_store`
  # But RuCaptcha requirements cache_store not in [:null_store, :memory_store, :file_store]
  # 默認：會從 Rails 配置的 cache_store 里面讀取相同的配置信息，並嘗試用可以運行的方式，用於存儲驗證碼字符
  # 但如果是 [:null_store, :memory_store, :file_store] 之类的，你可以通過下面的配置項單獨給 RuCaptcha 配置 cache_store
  self.cache_store = :file_store
  # 如果想要 disable cache_store 的 warning，就設置為 true，default false
  # self.skip_cache_store_check = true
  # Chars length, default: 5, allows: [3 - 7]
  # self.length = 5
  # enable/disable Strikethrough.
  # self.strikethrough = true
  # enable/disable Outline style
  # self.outline = false
end