Added comment to cta_catalogue_db.conf.example that explains which connection...

Added comment to cta_catalogue_db.conf.example that explains which connection string should be used when

catalogue/cta_catalogue_db.conf.example

@@ -17,7 +17,7 @@
 # This file should contain one and only one connection string.  Blank lines and
 # comments are ignored.
 #
-# Please note that comments on the end of a line are not supported.  Only entire
+# PLEASE NOTE that comments at the end of a line are not supported.  Only entire
 # line comments are allowed.  A comment line starts a hash '#' character.
 # Leading whitespace is permitted.
 #
@@ -32,4 +32,7 @@
 # or:
 #
 #    sqlite:filename
-
+#
+# PLEASE NOTE that the "in_memory" and "sqlite:" connection strings are for
+# development and testing.  Only the "oracle:" connection string should be used
+# in production.