Change Messages table url column to text

Fixes CNVS-21253

Test plan:
Tests pass (manual QA is N/A)

Change-Id: Iba5634b948e5857682cf574bf93160893f107461
Reviewed-on: https://gerrit.instructure.com/58351
Reviewed-by: Rob Orton <rob@instructure.com>
Tested-by: Jenkins
Reviewed-by: Joel Hough <joel@instructure.com>
Product-Review: Matthew Wheeler <mwheeler@instructure.com>
QA-Review: Matthew Wheeler <mwheeler@instructure.com>

app/models/message.rb

@@ -64,6 +64,7 @@ class Message < ActiveRecord::Base
   validates_length_of :transmission_errors, :maximum => maximum_text_length, :allow_nil => true, :allow_blank => true
   validates_length_of :to, :maximum => maximum_text_length, :allow_nil => true, :allow_blank => true
   validates_length_of :from, :maximum => maximum_text_length, :allow_nil => true, :allow_blank => true
+  validates_length_of :url, :maximum => maximum_text_length, :allow_nil => true, :allow_blank => true
 
   # Stream policy
   on_create_send_to_streams do

db/migrate/20150713214318_change_messages_url_to_text.rb

@@ -0,0 +1,11 @@
+class ChangeMessagesUrlToText < ActiveRecord::Migration
+  tag :postdeploy
+
+  def self.up
+    change_column :messages, :url, :text
+  end
+
+  def self.down
+    change_column :messages, :url, :string
+  end
+end

spec/models/message_spec.rb

@@ -458,4 +458,10 @@ describe Message do
     end
   end
 
-end
+  it 'allows urls > 255 characters' do
+    url = "a" * 256
+    msg = Message.new
+    msg.url = url
+    msg.save!
+  end
+end