add comment about bulk loading with CouchDB
add comment about bulk loading with CouchDB

vrsource/mapproxy,olt/mapproxy,procrastinatio/mapproxy,kaiCu/mapproxy,camptocamp/mapproxy,faegi/mapproxy,Anderson0026/mapproxy,camptocamp/mapproxy,geoadmin/mapproxy,drnextgis/mapproxy,faegi/mapproxy,mapproxy/mapproxy,kaiCu/mapproxy,drnextgis/mapproxy,procrastinatio/mapproxy,Anderson0026/mapproxy,vrsource/mapproxy,mapproxy/mapproxy,geoadmin/mapproxy,olt/mapproxy