Merges multiple slices into one without duplicates.

merge.go

// Merges slices into one without duplicates
func merge(slices... []string) []string {
	merged := *new([]string)
	// Use a map for faster lookup
	contains := map[string]bool{}

	for _, v := range slices {
		for _, s := range v {
			if _, ok := contains[s]; ok {
				// already contains. Skip!
				continue
			}
			// append.
			merged = append(merged, s)
			contains[strings.ToLower(s)] = true
		}

	}
	return merged
}