Use debug module to print sql for debugging purposes

lib/cartodb/models/dataview/list.js

@@ -1,4 +1,5 @@
 const BaseDataview = require('./base');
+const debug = require('debug')('windshaft:dataview:list');
 
 const TYPE = 'list';
 
@@ -12,7 +13,7 @@ const listSqlTpl = ctx => `select ${ctx._columns} from (${ctx._query}) as _cdb_l
     }
 }
 */
-module.exports = class List extends BaseDataview{
+module.exports = class List extends BaseDataview {
     constructor (query, options = {}) {
         super();
 
@@ -38,6 +39,8 @@ module.exports = class List extends BaseDataview{
             _columns: this.columns.join(', ')
         });
 
+        debug(listSql);
+
         return callback(null, listSql);
     }