Imports github.com/nlopes/slack github.com/uffish/holidays github.com/uffish/holidays/austria golang.org/x/net/context golang.org/x/oauth2 golang.org/x/oauth2/google google.golang.org/api/calendar/v3 gopkg.in/yaml.v1 Standard library imports bytes encoding/json errors flag fmt io/ioutil log math/rand net/http net/smtp net/url os os/user path path/filepath regexp strings time