Be more informative: add available profile options

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

bookstore/src/main/resources/application.properties

@@ -1,5 +1,12 @@
 # Pekka Helenius <fincer89@hotmail.com>, Fjordtek 2020
 
+
+
+# Recognized profiles:
+#
+# dev  :: for development
+# prod :: for production
+#
 spring.profiles.active     = dev
 
 # Default HTTP TCP port number for this server application