HTML field in RawTextDescription

In order to update your DB you have to launch the following SQL query:
  ALTER TABLE `projects_rawtextdescription` ADD `description_html` longtext NOT NULL AFTER `description`;

The HTML content will automatically be generated at the first call to save() or get_safe_html() of that object.

Advantages:
+ rawtext to html conversion is not a problem in terms of efficiency

Drawbacks:
+ update rawtext conversion => reset html field to its new value
+ store more data