Do not forget to use the password.

see #1

installer.cfg

@@ -4,7 +4,8 @@ tls_cert_file = /etc/ssl/certs/ssl-cert-snakeoil.pem
 
 [database]
 # Select database engine : postgres or mysql
-engine = postgres
+#engine = postgres
+engine = mysql
 host = 127.0.0.1
 install = true
 

modoboa_installer/scripts/modoboa.py

@@ -104,7 +104,8 @@ class Modoboa(base.Installer):
                 "INSERT INTO lib_parameter (name, value) VALUES ('{0}', '{1}')"
                 .format(name, value)
             )
-            self.backend._exec_query(query, self.dbname, self.dbuser)
+            self.backend._exec_query(
+                query, self.dbname, self.dbuser, self.dbpasswd)
 
     def post_run(self):
         """Additional tasks."""