diff --git a/README.md b/README.md
index e08dcee..a11e46f 100644
--- a/README.md
+++ b/README.md
@@ -6,10 +6,10 @@ It is based on [wojtek77/chat](https://github.com/wojtek77/chat), itself based o
 ## Features
 
 - No need for users to register. Just need the web address.
-- On connection, the page is feeded with the 50 last messages.
-- Optional *get* arguments to specify the user name and the room.    
+- On connection, the page is feeded with the 50 last messages of the day
+- Args are in the URL as *get* arguments, so that you can share the URL or make it a favorite    
 Example : `https://yourdomain.org/minchat/?room=Living&name=John`
-- Mono room (for now)
+- Optionaly multi room
 
 ## Installation
 ### On Yunohost
@@ -17,5 +17,17 @@ Via the admin web console, type in: <https://github.com/chtixof/minchat_ynh>
 Or on ssh : `sudo yunohost app install https://github.com/chtixof/minchat_ynh`
 ### Otherwise
 Download, unzip and just copy the content of the `sources` folder to any folder of your web site.
+## Setup
+On the application folder of your site, edit the file `conf/setup.ini`. The interesting parameter is `auth` that indicates which user is authorized to which room.
+
+In this example `auth = John:Game,Mary:Game,John:Family,Tim:Family,admin:,:Public`,
+- John can access the Game room, the Family room and the Public room
+- Mary can access the Game room and the Public room
+- Tim can access the Family room and the Public room
+- admin can access all rooms
+- other users can only acccess the Public room
+
+If `auth` is not set (default), there is a single unnamed room, opened to all users.
+
 ## Screen shot
 ![screenshot](https://raw.githubusercontent.com/chtixof/databank/master/minchat_ynh/minchat_ynh_screenshot01.gif)
\ No newline at end of file
diff --git a/sources/index.php b/sources/index.php
index ee38b6c..a497a3d 100644
--- a/sources/index.php
+++ b/sources/index.php
@@ -49,13 +49,19 @@ if (isset($_REQUEST['room'])) {
    $room = stripslashes(htmlspecialchars($_REQUEST['room']));
 }
 
+// no auth = single room = no room specified
+if ($auth[0]==""){$room="";}
+
 // check args
 if ($name.$room=="") {
   // no args
   $prompt = "Please fill in the form to continue:";
 } else {
   if ($name=="")  {$prompt = "<em>User name missing.</em>";}
-  else if ($room=="") {$prompt="<em>Room missing.</em>";}
+  else if ($room=="") {
+    if ($auth[0]==""){$prompt="";}
+    else {$prompt="<em>Room missing.</em>";}
+  } 
   else if (in_array($name.":".$room,$auth)) {$prompt="";}
   else if (in_array(":".$room,$auth)) {$prompt="";}
   else if (in_array($name.":",$auth)) {$prompt="";}
@@ -79,9 +85,11 @@ if ($name.$room=="") {
       echo '</p><form action="" method="get" class="tform"><p><label for="name">Name:</label><input type="text" name="name" id="name" value="';
       echo $name;
       echo '"/></p>';
-      echo '<p><label for="room">Room:</label><input type="text" name="room" id="room" value="';
-      echo $room;
-      echo '"/></p>';
+      if ($auth[0]!==""){
+        echo '<p><label for="room">Room:</label><input type="text" name="room" id="room" value="';
+        echo $room;
+        echo '"/></p>';
+      }
       echo '<br/><input type="submit" value="Enter" /></p></form></div>';
     } else {
       deleteOldHistory();
diff --git a/sources/post.php b/sources/post.php
index 3a397c9..f6e2243 100644
--- a/sources/post.php
+++ b/sources/post.php
@@ -25,7 +25,7 @@ $name = isset($_POST['name']) ? $_POST['name'] : '';
 $room = isset($_POST['room']) ? $_POST['room'] : '';
 $delay = isset($_POST['delay']) ? $_POST['delay'] : '';
 
-if ($text === '' || $name === '' || $room === '' || $delay === '') return;
+if ($text === '' || $name === '' || $delay === '') return;
 
 $isApc = extension_loaded('apc');
 
diff --git a/sources/server.php b/sources/server.php
index 1855d58..c8820e4 100644
--- a/sources/server.php
+++ b/sources/server.php
@@ -23,7 +23,7 @@ function vvv($var, & $result = null, $is_view = true)
 $id = isset($_POST['id']) ? $_POST['id'] : '';
 $room = isset($_POST['room']) ? $_POST['room'] : '';
 
-if ($id === '' || $room === '') return;
+if ($id === '' ) return;
 
 $isApc = extension_loaded('apc');
 $cache = $isApc ? apc_fetch('chat') : @unserialize(file_get_contents('./history/'.$room.'cache2100-01-01'));