Diu-Database (fictional world concept)

These days i keep my eyes open for a free and good solution about a wiki-system, because the plan is to build up a database of knowledge about the world 'Diu', this database will be defined as 'fictional world concept'.
The target is to define this world as detailed and plausible as possible.
Later on this knowledge might be expanded by community work (under the aspect of 'certificated' content, so content that is verified and agreedto be part of this world).
'Diu' is the first world falling under the concept-type 'fictional worlds', other worlds, which are already in progress, should follow (so like 'kenauer' or 'arkthal edliam').