Improve documentation for posting metrics

[ctoto93]

Here is my code to post metrics. Metrics explorer could not find the sent metrics.
But there is no error shown

    datadogClient := datadog.NewClient(config.API_KEY,config.APP_KEY)

    data := []datadog.DataPoint{datadog.DataPoint{1.0,15.0}}

    test:= datadog.Metric{}
    test.Metric = "order"
    test.Host = "golife"
    test.Points = data

    fmt.Println(test)

    err = datadogClient.PostMetrics([]datadog.Metric{test})
    if err != nil{
        panic(err)
    }

[seiffert]

@ctoto93 the first value you pass into a datadog.DataPoint needs to be a UNIX timestamp which is documented here: https://github.com/zorkian/go-datadog-api/blob/master/series.go#L13-L15

Please try something like datadog.DataPoint{float64(time.Now().Unix()), 15.0} and let us know whether that works for you.

[thdxr]

Follow up on this, I couldn't find any docs for the list of Types you can specify with a metric. Any idea?

[ojongerius]

@seiffert care to raise a PR with an example in the Readme?