http: panic serving [::1]:57351: runtime error: invalid memory address or nil pointer dereference
goroutine 18 [running]:
net/http.(*conn).serve.func1(0x18af8240, 0xf764a130, 0x18aec1d8)
    /Users/fz/projects/go15/src/net/http/server.go:1287 +0xa2
sync/atomic.AddUint64(0x18a8c454, 0x1, 0x0, 0x806559a, 0x18aeabd0)
    /Users/fz/projects/go15/src/sync/atomic/asm_386.s:112 +0xc
github.com/centrifugal/centrifugo/libcentrifugo.(*metricCounter).Add(0x18a8c454, 0x1, 0x0, 0x9, 0x18aeabc0)
    /private/var/www/different/go/gopath/src/github.com/centrifugal/centrifugo/libcentrifugo/metrics.go:129 +0x89
github.com/centrifugal/centrifugo/libcentrifugo.(*metricCounter).Inc(0x18a8c454, 0x18aeabb0, 0xf778a25c)
    /private/var/www/different/go/gopath/src/github.com/centrifugal/centrifugo/libcentrifugo/metrics.go:118 +0x31
github.com/centrifugal/centrifugo/libcentrifugo.(*Application).APIHandler(0x18a14900, 0xf764a218, 0x18b56100, 0x18afa310)
    /private/var/www/different/go/gopath/src/github.com/centrifugal/centrifugo/libcentrifugo/handlers.go:318 +0x43
github.com/centrifugal/centrifugo/libcentrifugo.(*Application).APIHandler-fm(0xf764a218, 0x18b56100, 0x18afa310)
    /private/var/www/different/go/gopath/src/github.com/centrifugal/centrifugo/libcentrifugo/handlers.go:103 +0x38
net/http.HandlerFunc.ServeHTTP(0x18b171c8, 0xf764a218, 0x18b56100, 0x18afa310)
    /Users/fz/projects/go15/src/net/http/server.go:1422 +0x34
github.com/centrifugal/centrifugo/libcentrifugo.(*Application).WrapShutdown.func1(0xf764a218, 0x18b56100, 0x18afa310)
    /private/var/www/different/go/gopath/src/github.com/centrifugal/centrifugo/libcentrifugo/handlers.go:470 +0x9d
net/http.HandlerFunc.ServeHTTP(0x18b0b190, 0xf764a218, 0x18b56100, 0x18afa310)
    /Users/fz/projects/go15/src/net/http/server.go:1422 +0x34
github.com/centrifugal/centrifugo/libcentrifugo.(*Application).Logged.func1(0xf764a218, 0x18b56100, 0x18afa310)
    /private/var/www/different/go/gopath/src/github.com/centrifugal/centrifugo/libcentrifugo/handlers.go:486 +0x105
net/http.HandlerFunc.ServeHTTP(0x18b0b1a0, 0xf764a218, 0x18b56100, 0x18afa310)
    /Users/fz/projects/go15/src/net/http/server.go:1422 +0x34
net/http.(*ServeMux).ServeHTTP(0x18b184a0, 0xf764a218, 0x18b56100, 0x18afa310)
    /Users/fz/projects/go15/src/net/http/server.go:1699 +0x133
net/http.serverHandler.ServeHTTP(0x18b58540, 0xf764a218, 0x18b56100, 0x18afa310)
    /Users/fz/projects/go15/src/net/http/server.go:1862 +0x156
net/http.(*conn).serve(0x18af8240)
    /Users/fz/projects/go15/src/net/http/server.go:1361 +0xc05
created by net/http.(*Server).Serve
    /Users/fz/projects/go15/src/net/http/server.go:1910 +0x343
^C[I]: 2016/02/25 12:50:06 Signal received: interrupt
[I]: 2016/02/25 12:50:06 Shutting down

{
"secret": "secret",
      "publish": false,
      "watch": true,
      "presence": true,
      "join_leave": false,
  "insecure_api" : true,
  "history_size": 10,
  "history_lifetime": 240,
  "log_level": "debug"
}