title: how to set mysql2 timezone option to remove query warning
body: <p>I always get warning  when use mysql2 do query</p>
  
  <pre><code>/usr/local/lib/ruby/gems/1.9.1/gems/mysql2-0.2.6/lib/active_record/connection_adapters/mysql2_adapter.rb:463: warning: :database_timezone option must be :utc or :local - defaulting to :local
  </code></pre>
  
  <p>I did see a  option for   Timezones</p>
  
  <p>Mysql2 now supports two timezone options:</p>
  
  <pre><code>  :database_timezone - this is the timezone Mysql2 will assume fields are already stored as, and will use this when creating the initial Time objects in ruby
    :application_timezone - this is the timezone Mysql2 will convert to before finally handing back to the caller
  </code></pre>
  
  <p>did any one know, how to usage, and where to set this option?</p>
  
  <p>Thanks.</p>