Add necessary security configuration for public web

Signed-off-by: Pekka Helenius <fincer89@hotmail.com>

bookstore/src/main/resources/application-prod.properties

@@ -3,4 +3,8 @@
 # Production configuration
 #
 # NOTE: Database configuration should be provided in additional
-# database-prod.properties file.
+# database-prod.properties file.
+
+# Enable production environment restrictions?
+security.enabled        = true
+security.book.count.max = 5