Top level constant referenced by warning for Mongoid model

I have the following mongoid model that inherits from the Entry model:

class Entry::Twitter < Entry

  field :retweet_count, :type => Integer, :default => 0
  field :retweeted, :type => Boolean, :default => false
  field :favorited, :type => Boolean, :default => false

  # in_reply_to_screen_name, in_reply_to_status_id_str, in_reply_to_user_id_str
  field :reply, :type => Hash

  field :from, :type => Hash # user: id_str, name, screen_name
  field :time, :type => Time # created_at
  field :data, :type => Hash # entities (hashtags and user_mentions)
  field :assets, :type => Hash # urls from original entities
  field :service, :type => String, :default => "twitter"

  attr_accessible :assets

  # validations
  validates_presence_of :retweet_count, :from, :time, :data

  # override set_service cause of https://github.com/sferik/twitter/issues/303

  def set_service
    self.service = "twitter"
  end
end

When i try to reference it i get the following warning:

ruby-1.9.3-p125 :001 > Entry::Twitter
(irb):1: warning: toplevel constant Twitter referenced by Entry::Twitter
=> Twitter

Instead of referencing to my model it references to the Top Level Constant Twitter that is defined by a gem.

What can i do to fix this? I don't want to use another name for my class.