#railsで複数tweetを連投(スレッド投稿)する
前提

gem 'twitter'
twitterで各app key,secret,access token,access token secret 取得済み

@post.tweets = ["tweet1","tweet2","teet3"]

posts_controller.rb

class PostsController < ApplicationController

...

  client = Twitter::REST::Client.new do |config|
    config.consumer_key         = ENV['TWITTER_KEY']
    config.consumer_secret      = ENV['TWITTER_SECRET']
    config.access_token         = ENV['ACCESS_TOKEN']
    config.access_token_secret  = ENV['ACCESS_TOKEN_SECRET']
  end

  @tw_ids = Array.new
  @post.tweets.each_with_index do |tw, i|
    if i < 1
      res = client.update(tw)
      @res_ids.push(res.id)
    else
      res = client.update(tw, {:in_reply_to_status_id => @tw_ids.last})
      @tw_ids.push(res.id)
    end
  end

...

end

みたいな感じ。