Add the google file system (#522)

* Re-orders entries and adds PDF of The Google File System

datastores/README.md

@@ -44,6 +44,8 @@
 
 ## Hosted Papers
 
+* :scroll: [A Solution to the Network Challenges of Data Recovery in Erasure-coded Distributed Storage Systems: A Study on the Facebook Warehouse Cluster](network-challenges-of-data-recovery-in-erasure-coded-distributed-storage-systems.pdf)
+
 * :scroll: [Bigtable: A Distributed Storage System for Structured Data](bigtable-a-distributed-storage-system-for-structured-data.pdf)
 
 * :scroll: [Database Metatheory: Asking Big Queries](database-metatheory--asking-the-big-queries.pdf)
@@ -54,14 +56,16 @@
 
 * :scroll: [Freenet: A Distributed Anonymous Information Storage and Retrieval System](freenet-a-distributed-anonymous-information-and-retrieval-system.pdf)
 
-* :scroll: [Megastore: Providing Scalable, Highly Available Storage for Interactive Services](megastore-providing-scalable-highly-available-storage-for-interactive-services.pdf)
+* :scroll: [The Google File System](the-google-file-system.pdf)
 
-* :scroll: [A Solution to the Network Challenges of Data Recovery in Erasure-coded Distributed Storage Systems: A Study on the Facebook Warehouse Cluster](network-challenges-of-data-recovery-in-erasure-coded-distributed-storage-systems.pdf)
+* :scroll: [Megastore: Providing Scalable, Highly Available Storage for Interactive Services](megastore-providing-scalable-highly-available-storage-for-interactive-services.pdf)
 
 * :scroll: [RADOS: A Scalable, Reliable Storage Service for Petabyte-scale Storage Clusters](rados-a-scalable-reliable-storage-service-for-petabyte-scale-storage-clusters.pdf)
 
 * :scroll: [Spanner: Google’s Globally-Distributed Database](spanner-google's-globally-distributed-database.pdf)
 
+* :scroll: [Spartan: A distributed array framework with smart tiling](spartan-a-distributed-array-framework-with-smart-tiling.pdf)
+
 * :scroll: [Stasis: Flexible Transactional Storage](stasis-flexible-transactional-storage.pdf)
 
 * :scroll: [TAO: Facebooks Distributed Data Store for the Social Graph'](tao-facebook-distributed-datastore.pdf)
@@ -70,4 +74,3 @@
 
 * :scroll: [Warp: Multi-Key Transactions for Key-Value Stores](warp-multi-key-transactions-for-key-value-stores.pdf)
 
-* :scroll: [Spartan: A distributed array framework with smart tiling](spartan-a-distributed-array-framework-with-smart-tiling.pdf)