Add a how it works section to readme

Author: bhargavms

README.md

@@ -1,2 +1,21 @@
-# sqlite-persistent-queue
+# SQLite based Persistent Queue.
+
 A Java Queue interface implementation that stores directly to SqliteDb
+
+## How it works
+
+ * Implement the `QueueObjectConverter<T>` interface do decide how you want to serialize and
+   deserialize the objects that you want to push to the Queue.
+
+ * The `SQLitePersistentQueue` class uses the above implementation to serialize objects before storing
+   it the Database.
+
+ * Upon calling `poll()` or `remove()` on the `SQLitePersistentQueue` the item with the lowest primary
+   key value (since the primary key is auto-incrementing) is removed from the Queue and returned. This
+   co-incidentally is the HEAD of the queue (as queue is FIFO based).
+
+ * Please remember each instance of SQLitePersistentQueue creates a new connection to the Database.
+   I have kept the freedom of how many connections to be made to DB to the developer. The ideal usage
+   for new developers would be to hold only a single instance of the `SQLitePersistentQueue` class
+   in your Application class, and retrieve this wherever you want. Also **DO NOT** forget to call `close()`
+   to close the connection to the Database once you are finished using the Queue.