Correction so that the tweet url is actually well generated

app/models/event.rb

@@ -103,12 +103,16 @@ class Event < ActiveRecord::Base
     "#{start_time.to_date} #{city}: #{title} #{hashtags.join(' ')}"
   end
 
-  def to_tweet(url)
-    tweet = to_s
-    if (tweet.size + url.size >= 140)
-      tweet = tweet[0, tweet[0, 140 - url.size].rindex(/\s/)]
+  def to_tweet
+    url = Rails.application.routes.url_helpers.event_url(
+      self,
+      host: ActionMailer::Base.default_url_options[:host])
+
+    tweet = "#{self} #{url}"
+    if (tweet.size >= 140)
+      tweet = "#{tweet[0, tweet.rindex(/\s/, 140 - url.size)]} #{url}"
     end
-    "#{tweet} #{url}"
+    tweet
   end
 
   private

app/models/event_callbacks.rb

@@ -33,6 +33,6 @@ class EventCallbacks
       config.access_token        = ENV['TWITTER_ACCESS_TOKEN']
       config.access_token_secret = ENV['TWITTER_ACCESS_SECRET']
     end
-    client.update "#{event.to_tweet event_url(event)}" if client.consumer_key
+    client.update event.to_tweet if client.consumer_key
   end
 end

app/views/moderations/validate.html.haml

@@ -22,7 +22,7 @@
 
     %h3= t '.tweet_helper'
 
-    = @event.to_tweet event_url @event
+    = @event.to_tweet
 
 %fieldset
   %legend