add installation instructions to pkg packages

pkg/serialization/lib/serialization.dart

Index: pkg/serialization/lib/serialization.dart
diff --git a/pkg/serialization/lib/serialization.dart b/pkg/serialization/lib/serialization.dart
index 130be2741fa33dfd53dfdbeb26d59927353a605c..d8283bf8564bfbdb83d548460e396671c6ec11dd 100644
--- a/pkg/serialization/lib/serialization.dart
+++ b/pkg/serialization/lib/serialization.dart
@@ -7,6 +7,16 @@
  * [Serialization] is defined in terms of [SerializationRule]s and supports
  * reading and writing to different formats.
  *
+ * ## Installing ##
+ *
+ * Use [pub][] to install this package. Add the following to your `pubspec.yaml`
+ * file.
+ *
+ *     dependencies:
+ *       serialization: any
+ *
+ * And then run `pub install`.
+ *
  * Setup
  * =====
  * A simple example of usage is
@@ -181,6 +191,8 @@
  *     new Serialization()
  *       ..addRuleFor(new Person(), constructorFields: ["name"])
  *       ..namedObjects['Person'] = reflect(new Person()).type;
+ *
+ * [pub]: http://pub.dartlang.org
  */
 library serialization;