unable to load driver packages

CODE:-

import (
"database/sql"
"fmt"
_"github.com/ibmdb/go_ibm_db"
)

func main() {
con := "HOSTNAME=localhost;PORT=50000;DATABASE=go;UID=*****;PWD=******;"
db, err := sql.Open("go_ibm_db", con)
fmt.Println(err)
}
main()

ERROR:-
This is Open()------722
sql: unknown driver "go_ibm_db" (forgotten import?)

Thanks.