WIP - Integrate with InfluxDB instead of KeenIO

I really wish there was an easier way to do this mapping (`ENV -> config`). At one stage I think @JonathonMA wrote a library to handle it but it was a bit more code than manually typing it out like you've done here. Just for shits and giggles I think the following would work but it definitely feels more magical (I'd stick with what you have).

``` ruby
ENV
  .select { |key, _value| key.starts_with?("INFLUXDB_") }
  .each_with_object({}) { |(key, value), config| config[key.replace("INFLUXDB_").downcase] = value }
```