Wrong timezone for the charts

[SergeBredin]

[SergeBredin]

;-)

[vallettea]

The problem comes from the sensors.
I did a hack to use the created_at field of the database instead of date which means we assume that the measurement was done at the moment the data is received. It's not the best but it works.

For the reminder

https://pheromon.ants.builders/measurements/place/raw?id=20&type=wifi&start=2016-05-17%2006:00:00.0000&end=2016-05-17%2018:00:00.0000

was helpful for debugging.