add instructions for a mapuser
add instructions for a mapuser

dbirchak/CartoDB-SQL-API,CartoDB/CartoDB-SQL-API,dbirchak/CartoDB-SQL-API,calvinmetcalf/CartoDB-SQL-API,CartoDB/CartoDB-SQL-API,dbirchak/CartoDB-SQL-API,calvinmetcalf/CartoDB-SQL-API,calvinmetcalf/CartoDB-SQL-API,calvinmetcalf/CartoDB-SQL-API,dbirchak/CartoDB-SQL-API