Added new option to generate config file.

fix #130

run.py

@@ -23,6 +23,9 @@ def main():
                         help="Force installation")
     parser.add_argument("--configfile", default="installer.cfg",
                         help="Configuration file to use")
+    parser.add_argument(
+        "--stop-after-configfile-check", action="store_true", default=False,
+        help="Check configuration, generate it if needed and exit")
     parser.add_argument("domain", type=str,
                         help="The main domain of your future mail server")
     args = parser.parse_args()
@@ -31,6 +34,8 @@ def main():
         utils.ENV["debug"] = True
     utils.printcolor("Welcome to Modoboa installer!", utils.GREEN)
     utils.check_config_file(args.configfile)
+    if args.stop_after_configfile_check:
+        return
     config = configparser.SafeConfigParser()
     with open(args.configfile) as fp:
         config.readfp(fp)