---

--- add markdown to list of constraints (which is currently just

--- relevant for upgrades, since new installations did not have this

--- constraint.

--- 

ALTER TABLE forums_messages
     DROP constraint IF EXISTS static_p_c_format_ck;

ALTER TABLE forums_messages
     ADD constraint static_p_c_format_ck
     CHECK (format in ('text/enhanced', 'text/markdown', 'text/plain', 'text/fixed-width', 'text/html'));