fix for in queries in pg
fix for in queries in pg

waterlinejs/waterline-sequel,icirellik/waterline-sequel,ryanwilliamquinn/waterline-sequel,takayukii/waterline-sequel,appscot/waterline-sequel-orientdb,balderdashy/waterline-sequel,jianpingw/waterline-sequel,devinivy/waterline-sequel,anotherpit/waterline-sequel,mitom/waterline-sequel-orientdb,goraSi/waterline-sequel,Shyp/waterline-sequel