Solution: $ rake db:migrate This is what happens in pg when you don't run rake db:migrate

ActiveRecord::StatementInvalid in MessagesController#new

ActiveRecord::StatementInvalid in MessagesController#new

PG::Error: ERROR:  relation "messages" does not exist
LINE 5:              WHERE a.attrelid = '"messages"'::regclass
                                        ^
:             SELECT a.attname, format_type(a.atttypid, a.atttypmod),
                     pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod
              FROM pg_attribute a LEFT JOIN pg_attrdef d
                ON a.attrelid = d.adrelid AND a.attnum = d.adnum
             WHERE a.attrelid = '"messages"'::regclass
               AND a.attnum > 0 AND NOT a.attisdropped
             ORDER BY a.attnum