title: Rails 4 Migration: Mysql2::Error: Data too long for column 'xxxx'
body: <p>Here is my schema.rb</p>
  
  <pre><code>  create_table "users", force: true do |t|
      t.string   "name",       limit: 6
      t.string   "email"
      t.datetime "created_at"
      t.datetime "updated_at"
    end
  </code></pre>
  
  <p>I set the limit fo string for the column "name".</p>
  
  <p>Then, in console:</p>
  
  <pre><code> user = User.new(name:"1234567890",email:"username@gmail.com")
   user.save!
  </code></pre>
  
  <p>It raised the error:</p>
  
  <pre><code>ActiveRecord::StatementInvalid: Mysql2::Error: Data too long for column 'name' at row 1: INSERT INTO `users` (`created_at`, `email`, `name`, `updated_at`) VALUES ('2014-06-19 15:08:15', 'username@gmail.com', '1234567890', '2014-06-19 15:08:15')
  </code></pre>
  
  <p>But, when I switched to <em>rails 3</em>.</p>
  
  <p>I found it truncated the string "<strong><em>1234567890</em></strong>" automatically, and inserted "<strong><em>123456</em></strong>" into database without error.</p>
  
  <p>Is there anything about this has been removed in <em>rails 4</em>?</p>
  
  <p>Should I add some truncate functions in the model by myself? Thanks!</p>