add vendoring with go dep

vendor/github.com/influxdata/influxdb/pkg/slices/strings.go

@@ -0,0 +1,41 @@
+// Package slices contains functions to operate on slices treated as sets.
+package slices // import "github.com/influxdata/influxdb/pkg/slices"
+
+import "strings"
+
+// Union combines two string sets.
+func Union(setA, setB []string, ignoreCase bool) []string {
+	for _, b := range setB {
+		if ignoreCase {
+			if !ExistsIgnoreCase(setA, b) {
+				setA = append(setA, b)
+			}
+			continue
+		}
+		if !Exists(setA, b) {
+			setA = append(setA, b)
+		}
+	}
+	return setA
+}
+
+// Exists checks if a string is in a set.
+func Exists(set []string, find string) bool {
+	for _, s := range set {
+		if s == find {
+			return true
+		}
+	}
+	return false
+}
+
+// ExistsIgnoreCase checks if a string is in a set but ignores its case.
+func ExistsIgnoreCase(set []string, find string) bool {
+	find = strings.ToLower(find)
+	for _, s := range set {
+		if strings.ToLower(s) == find {
+			return true
+		}
+	}
+	return false
+}