Problem following instructions installing Mattermost 2.2.0 in Ubuntu 14.04 + connecting 3 ubuntu machines

Hello @crspeller, I got blocked by akismet.

For the previous question, I did redo on the platform

root@Mattermost-Server:/opt/timmy/mattermost/mattermost/bin# ./platform
[15:16:57 EDT 2016/04/28] [INFO] (github.com/mattermost/platform/utils.GetTranslationsBySystemLocale:52) Loaded system translations for 'en' from '/opt/timmy/mattermost/mattermost/i18n/en.json'
[2016/04/28 15:16:57 EDT] [INFO] Current version is 2.2.0 (6671/Fri Apr 15 18:40:19 UTC 2016/8e883ad2f516820942cc0131241268c1ea909ff3)
[2016/04/28 15:16:57 EDT] [INFO] Enterprise Enabled: false
[2016/04/28 15:16:57 EDT] [INFO] Current working directory is /opt/timmy/mattermost/mattermost/bin
[2016/04/28 15:16:57 EDT] [INFO] Loaded config file from /opt/timmy/mattermost/mattermost/config/config.json
[2016/04/28 15:16:57 EDT] [INFO] Server is initializing...
[2016/04/28 15:16:57 EDT] [INFO] Pinging sql master database
[2016/04/28 15:16:57 EDT] [CRIT] Failed to ping db err:dial tcp: lookup dockerhost on 8.8.8.8:53: no such host
panic: Failed to open sql connection dial tcp: lookup dockerhost on 8.8.8.8:53: no such host

goroutine 1 0x6, 0xc82032b930, 0x5, 0xc820477db0, 0x48, 0xa, 0xa, 0xc820217900, 0xc81ffef197)
/go/src/github.com/mattermost/platform/store/sql_store.go:169 +0x894
github.com/mattermost/platform/store.NewSqlStore(0x0, 0x0)
/go/src/github.com/mattermost/platform/store/sql_store.go:61 +0x11c
github.com/mattermost/platform/api.NewServer()
/go/src/github.com/mattermost/platform/api/server.go:35 +0xe8
main.main()
/go/src/github.com/mattermost/platform/mattermost.go:67 +0x74d

goroutine 17 [syscall, locked to thread]:
runtime.goexit()
/usr/local/go/src/runtime/asm_amd64.s:1721 +0x1

goroutine 5 /usr/local/go/src/os/signal/signal_unix.go:22 +0x18
created by os/signal.init.1
/usr/local/go/src/os/signal/signal_unix.go:28 +0x37

goroutine 245 /go/src/github.com/mattermost/platform/Godeps/_workspace/src/github.com/alecthomas/log4go/filelog.go:87 +0xabc
created by github.com/alecthomas/log4go.NewFileLogWriter
/go/src/github.com/mattermost/platform/Godeps/_workspace/src/github.com/alecthomas/log4go/filelog.go:119 +0x38b

goroutine 244 0x7ff6cdddd1e8, 0xc820026010)
/go/src/github.com/mattermost/platform/Godeps/_workspace/src/github.com/alecthomas/log4go/termlog.go:33 +0x69
created by github.com/alecthomas/log4go.NewConsoleLogWriter
/go/src/github.com/mattermost/platform/Godeps/_workspace/src/github.com/alecthomas/log4go/termlog.go:26 +0xb5

goroutine 246 /usr/local/go/src/database/sql/sql.go:634 +0x45
created by database/sql.Open
/usr/local/go/src/database/sql/sql.go:481 +0x336
Fist of all.. I got confused on several things for the second server

1. which directory I should install mattermost on?
   Instead of /home/ubuntu/mattermost i wrote opt/timmy/mattermost
   then i downloaded the file there and use tar.gz there.

2. How to create the ubuntu user, (in my case renamed timmy)?
   I used this line from rosehosting

   sudo adduser --home /opt/timmy --shell /bin/bash --gecos 'Mattermost application' timmy
   sudo install -d -m 755 -o timmy -g timmy /opt/timmy