add version constraints

list.go

@@ -3,6 +3,19 @@ package version
 // List is a slice of versions that implements sort.Interface.
 type List []*Version
 
+// Match tests versions against a constraint and returns a new List of matching versions only.
+func (list List) Match(c *Constraint) List {
+	filtered := List{}
+
+	for _, v := range list {
+		if v.Match(c) {
+			filtered = append(filtered, v)
+		}
+	}
+
+	return filtered
+}
+
 func (list List) Len() int {
 	return len(list)
 }