Removed database documentation default values for optional fields.
Removed database documentation default values for optional fields.

oesgalha/awesome_nested_set,rbo7nik/awesome_nested_set,markmercedes/awesome_nested_set,experteer/awesome_nested_set,sximba/rational_nested_set,collectiveidea/awesome_nested_set,petergoldstein/awesome_nested_set,sximba/rational_nested_set