Update README.md

Author: jodebrui

samples/README.md

@@ -1,5 +1,17 @@
 # Sample Categories
 
+__[applications] (applications/)__
+
+End-to-end sample applications that illustrate the use of SQL Server for specific application scenarios.
+
+__[databases] (databases/)__
+
+Sample databases for SQL Server, Azure SQL Database, and Azure SQL Data Warehouse.
+
 __[features] (features/)__
 
-Contains samples illustrating specific SQL Server and Azure SQL Database features, including In-Memory OLTP, Master Data Services (MDS), and R Services.
+Samples illustrating specific SQL Server and Azure SQL Database features, including In-Memory OLTP, Master Data Services (MDS), and R Services.
+
+__[management] (management/)__
+
+Samples that help with the management of SQL Server and Azure SQL Database.