DB hint

[vitaly-t]

From here: https://github.com/devinit/digital-platform/blob/d7e61b6718cb44973828de56983170b6f082d3d1/nodejs/js/db.js

• you should use tasks with pg-promise, see: tasks;
• tasks also support ES6 generators, so you do not need to use co at all
• you should not use connect at all, it is unnecessary for what you are doing there, and not safe