added tips goodie

lib/DDG/Goodie/Tips.pm

@@ -0,0 +1,30 @@
+package DDG::Goodie::Tips;
+use DDG::Goodie;
+
+triggers query_lc => qr/^(\d{1,3})(?: ?%| percent) (?:(tip (?:on|for))|of) ([\$\-]?)(\d+(\.?)(?(5)\d+))$/i;
+
+handle matches => sub {
+    my ($p, $is_tip, $sign,$num) = @_;
+    $p /= 100;
+    my $t = $p*$num;
+    my $tot;
+
+    if ($is_tip) {
+	$tot = $num + $t;
+    }
+
+    $t = sprintf "%.2f", $t;
+    $tot = sprintf "%.2f", $tot if $tot;
+
+    if ($tot) {
+	zci answer_type => 'tip';
+	return "Tip: \$$t  Total: \$$tot";
+    }
+    $t = $sign . $t;
+    $tot = $sign . $tot if $tot;
+    zci answer_type => 'percentage';
+    return "$t is ".($p*100)." percent of $sign$num";
+	
+};
+
+1;