Added Groovy implementation

Groovy/XOREncryption.groovy

@@ -0,0 +1,19 @@
+def encryptDecrypt(String input) {
+    def key = ['K', 'C', 'Q'] //Can be any chars, and any length array
+    def output = []
+
+    for(int i = 0; i < input.length(); i++) {
+		int a = input.charAt(i) as int;
+		int b = (key[i % key.size()] as char) as int
+        output.add((a ^ b) as char)
+    }
+
+    output.join("")
+}
+
+
+def encrypted = encryptDecrypt("kylewbanks.com")
+println("Encrypted:" + encrypted)
+
+def decrypted = encryptDecrypt(encrypted)
+println("Decrypted:" + decrypted)