[sql] preprocess_entity uses lgdb helper's SQL converters.
The preprocess_entity does not yield anymore the conversion logic for different
base types, but relies on a new SQL_CONVERTERS dictionary of the db helper.
This will allow later inclusion of new base types.
from cubicweb.schemas.base import in_group, CWSourceSchemaConfig
# copy __permissions__ to avoid modifying a shared dictionary
in_group.__permissions__ = in_group.__permissions__.copy()
in_group.__permissions__['read'] = ('managers',)
cw_for_source = CWSourceSchemaConfig.get_relation('cw_for_source')
cw_for_source.__permissions__ = {'read': ('managers', 'users'),
'add': ('managers',),
'delete': ('managers',)}