Add support for influxdb metrics

[axingblog]

Will you adding support for new metric targets influxdb?

[magiconair]

yes, once I finish the refactoring to support tags in metrics.

[ujenmr]

as workaround you can use telegraf's statsd input plugin
telegraf.conf

[[inputs.statsd]]
    service_address = ":8127"
    percentiles = [90]
    metric_separator = "_"
    parse_data_dog_tags = false
    allowed_pending_messages = 10000
    percentile_limit = 1000
    templates = [
        "fabio.* measurement.service-id.field*"
    ]

fabio.properties:

metrics.target = statsd
metrics.prefix = {{clean .Exec}}.{{clean .Hostname}}
metrics.names = {{clean .Service}}
metrics.statsd.addr = 172.17.0.1:8127

[magiconair]

Please see #211 (comment)