slack init: Simple interaction with slack bot

ref: https://github.com/nlopes/slack/blob/master/examples/websocket/websocket.go

Effect：

Send the command ads with text, which slack BOT returns.

package main

import (
    "fmt"
    "regexp"
    "github.com/nlopes/slack"
)

func main() {

    api := slack.New("your bot token")
    // slack.New("YOUR_TOKEN_HERE", slack.OptionDebug(true))

    rtm := api.NewRTM()  //Real-time message
    go rtm.ManageConnection()

    for msg := range rtm.IncomingEvents {
        fmt.Print("Event Received: ")
        switch ev := msg.Data.(type) {
        case *slack.HelloEvent:
            // Ignore hello

        case *slack.ConnectedEvent:
            fmt.Println("Infos:", ev.Info)
            fmt.Println("Connection counter:", ev.ConnectionCount)
            rtm.SendMessage(rtm.NewOutgoingMessage("Hello world", "CB9NY3BAP"))

        case *slack.MessageEvent:
            if(ev.Type == "message") {
                fmt.Printf("Message: %v
", ev)
                reg := regexp.MustCompile(`^adss`)  //Regular matching ads

                if(reg.MatchString(ev.Text)) {  //Receive commands starting with ads
                    fmt.Println(ev.Text)
                    rtm.SendMessage(rtm.NewOutgoingMessage(ev.Text, ev.Channel))  //Return the received text
                }
            }

        case *slack.PresenceChangeEvent:
            fmt.Printf("Presence Change: %v
", ev)

        case *slack.LatencyReport:
            fmt.Printf("Current latency: %v
", ev.Value)

        case *slack.RTMError:
            fmt.Printf("Error: %s
", ev.Error())

        case *slack.InvalidAuthEvent:
            fmt.Printf("Invalid credentials")
            return

        default:

            // Ignore other events..
             fmt.Printf("Unexpected: %v
", msg.Data)
        }
    }
}