title: Rails with mysql can't save json datatype
body: <p>I have create Rails(3.2) application with mysql(5.7.16) backend. I can't save json data and I have pass value like following and it shows error like </p>
  
  <blockquote>
    <p>ActiveRecord::StatementInvalid - Mysql2::Error: Invalid JSON text: "Invalid value." at position 1 in value for column 'shopping_cart_item_special_infos.special_info'.: INSERT INTO <code>shopping_cart_item_special_infos</code> (<code>created_at</code>, <code>shopping_cart_checkout_option_id</code>, <code>special_info</code>, <code>updated_at</code>) VALUES ('2016-12-29 06:08:52', 141, '--- !ruby/hash:ActiveSupport::HashWithIndifferentAccess\n\'201\': text1\n\'209\': \'623\'\n\'210\': \'625\'\n\'211\': text2\n', '2016-12-29 06:08:52'):
      activerecord (3.2.21) lib/active_record/connection_adapters/abstract_adapter.rb:285:in <code>rescue in log'
      activerecord (3.2.21) lib/active_record/connection_adapters/abstract_adapter.rb:280:in</code>log'
      newrelic_rpm (3.9.1.236) lib/new_relic/agent/instrumentation/active_record.rb:63:in `block in log_with_newrelic_i</p>
  </blockquote>
  
  <pre><code>{"201"=&gt;"text1", "209"=&gt;"623", "210"=&gt;"625", "211"=&gt;"text2"}
  </code></pre>
  
  <p>What was wrong here ?</p>