code: func initConfig() {
  	if configFile != "" { // enable ability to specify config file via flag
  		viper.SetConfigFile(configFile)
  	}
  
  	viper.SetConfigName("fusis") // name of config file (without extension)
  	viper.SetConfigType("toml")
  	viper.AddConfigPath(".")            // adding current directory as first search path
  	viper.AddConfigPath("$HOME/.fusis") // adding ~/.fusis as fallback
  	viper.AddConfigPath("/etc")         // adding /etc as next fallback
  	viper.AutomaticEnv()                // read in environment variables that match
  
  	// If a config file is found, read it in.
  	if err := viper.ReadInConfig(); err == nil {
  		log.Infof("Using config from %s", viper.ConfigFileUsed())
  	} else {
  		log.Fatal("Error reading config file: fusis.toml", err)
  		log.Fatal("Searched: ./, ~/fusis and /etc")
  	}
  
  }
docs: // initConfig reads in config file and ENV variables if set.