Added a README in castor/messsages

castor/messages/README

+/******************************************************************************
+ *                      messages/README
+ *
+ * This file is part of the Castor project.
+ * See http://castor.web.cern.ch/castor
+ *
+ * Copyright (C) 2003  CERN
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * 
+ *
+ * @author Castor Dev team, castor-dev@cern.ch
+ *****************************************************************************/
+
+Castor messages for internal communication are now described using Google's API protocol buffers.
+For writing a message, I let you look at the documentation 
+https://developers.google.com/protocol-buffers/docs/cpptutorial or at the existing messages.
+The syntax is fairly obvious.
+
+Transforming those messages into C++ code is done only once using these simple commands 
+> cd $CASTOR_SRC/castor/messages
+> protoc -I=. --cpp_out=. File.proto
+
+That command will generate File.pb.h and File.pb.cc into $CASTOR_SRC/castor/messages
+Then File.pb.cc has to be added to $CASTOR_SRC/castor/messages's CMakeList.txt 
+(in lib castorMessages)
+
+After add to git the 3 new files (proto, pb.h and pb.cc) and the updated CMakeList 
+then commit the changes
\ No newline at end of file