use correct demo account

README.md

 The fastest way to test it is to test the demo:
 
 * http://demo.archipeldata.com
-* login: demo@archipeldata.com
+* login: demo@localhost
 * password: demo
 
 ### Install your own instance ###
 
 If you need help, contact us. If you want to help, contact us. So... contact us ;)
 
-Damien Accorsi - damien.accorsi@free.fr
+Damien Accorsi - damien.accorsi@free.fr