func (p *Plugin) OnConfigurationChange() error {
	var c Configuration
	if err := p.API.LoadPluginConfiguration(&c); err != nil {
		p.API.LogError(err.Error())
		return err
	}
	p.welcomeMessages.Store(c.WelcomeMessages)
	return nil
}
OnConfigurationChange is invoked when configuration changes may have been made.
package main
const (
	actionTypeAutomatic = "automatic"
	actionTypeButton    = "button"
)
type ConfigMessageAction struct {
	ActionType string
	ActionDisplayName string
	ActionName string
	ActionSuccessfulMessage []string
	ChannelsAddedTo []string
}
type ConfigMessage struct {
	DelayInSeconds int
	Message []string
	AttachmentMessage []string
	TeamName string
	Actions []*ConfigMessageAction
}
type Configuration struct {
	WelcomeMessages []*ConfigMessage
}
func (p *Plugin) getWelcomeMessages() []*ConfigMessage {
	return p.welcomeMessages.Load().([]*ConfigMessage)
}