diff --git a/controllers/apis.rb b/controllers/apis.rb
index f9e3dd9..017534d 100644
--- a/controllers/apis.rb
+++ b/controllers/apis.rb
@@ -8,12 +8,11 @@ def self.read_body io, parse_json = true
     def self.included base
       base.class_eval do
 
-        before /^\/api\/(message|user|menu|media)/ do
+        before /^\/api\/(?<!token)/ do
           @app ||= Wecheat::Models::App.find_by_access_token(params[:access_token])
           halt(json errcode: 40012) if @app.nil?
         end
 
-        # to receive message from out-site app
         post '/api/message/custom/send' do
           Wecheat::Utils.log_received_message({app: @app.label, response: Apis.read_body(request.body, false)}.to_json)
           json errcode: 0
@@ -35,6 +34,50 @@ def self.included base
           json @app.user(params[:openid]) || {errcode: 46004}
         end
 
+        post '/api/groups/create' do
+          group = Wecheat::Models::Group.new(params[:group])
+          if group
+            @app.groups << group
+            @app.save
+            json group: group
+          else
+            json errcode: 40050
+          end
+        end
+
+        get '/api/groups/get' do
+          json groups: @app.groups.collect{|g| {id: g.id, name: g.name, count: @app.users.select{|u| u.group_id.to_s == g.id.to_s }.size } }
+        end
+
+        post '/api/groups/getid' do
+          if user = @app.user(params[:openid])
+            json group_id: user.group_id
+          else
+            json errcode: 40003
+          end
+        end
+
+        post '/api/groups/update' do
+          group = @app.group((params[:group]||{})[:id])
+          if group
+            group.name = params[:group][:name]
+            @app.save
+            json errcode: 0
+          else
+            json json errcode: 40050
+          end
+        end
+
+        post '/api/groups/members/update' do
+          if user = @app.user(params[:openid])
+            user.group_id = params[:to_groupid]
+            @app.save
+            json errcode: 0
+          else
+            json errcode: 40050
+          end
+        end
+
         post '/api/menu/create' do
           if data = Apis.read_body(request.body)
             @app.button = Wecheat::Models::Button.new(data)
diff --git a/models/app.rb b/models/app.rb
index 975aa57..59e0112 100644
--- a/models/app.rb
+++ b/models/app.rb
@@ -13,8 +13,8 @@ class App < Hashie::Dash
     property :url,  default: ''
     property :users, default: []
     property :medias, default: []
-    property :articles, default: []
     property :button
+    property :groups, default: []
 
     def self.find_by_access_token token
       self.all.select{|app| app.access_token == token }.first
@@ -61,8 +61,16 @@ def medias_by_type type
       self.medias.select{|m| m.type.to_s == type.to_s }
     end
 
-    def article id
-      find_resource :articles, :id, id
+    def group id
+      find_resource :groups, :id, id
+    end
+
+    def group_users gid
+      users.select{|u| u.group_id.to_s == gid.to_s }
+    end
+
+    def user_group_name u
+      (group(u.group_id)||{})[:name]
     end
 
     private
diff --git a/models/group.rb b/models/group.rb
new file mode 100644
index 0000000..16822f4
--- /dev/null
+++ b/models/group.rb
@@ -0,0 +1,13 @@
+module Wecheat::Models
+  class Group < Hashie::Dash
+    include Hashie::Extensions::IgnoreUndeclared
+    property :id, required: true
+    property :name, required: true, default: 'unamed'
+
+    def initialize(attributes = {}, &block)
+      attributes[:id] ||= Time.now.strftime('%s%L')
+      super(attributes, &block)
+    end
+
+  end
+end
\ No newline at end of file
diff --git a/models/media.rb b/models/media.rb
index 6c51e3a..bd0abb5 100644
--- a/models/media.rb
+++ b/models/media.rb
@@ -7,7 +7,7 @@ class Media < Hashie::Dash
     property :path, required: true, default: ''
 
     def initialize(attributes = {}, &block)
-      attributes[:id] ||= (Time.now.to_i | rand(100000))
+      attributes[:id] ||= Time.now.strftime('%s%L')
       super(attributes, &block)
     end
   end
diff --git a/models/user.rb b/models/user.rb
index 74578f9..de1e5a6 100644
--- a/models/user.rb
+++ b/models/user.rb
@@ -15,6 +15,7 @@ class User < Hashie::Dash
     property :latitude, required: true
     property :longitude, required: true
     property :precision, required: true
+    property :group_id
 
     def initialize(attributes = {}, &block)
       attributes[:openid] ||= Wecheat::Utils.rand_openid
diff --git a/views/_app_groups.erb b/views/_app_groups.erb
new file mode 100644
index 0000000..da6ca20
--- /dev/null
+++ b/views/_app_groups.erb
@@ -0,0 +1,12 @@
+<div class="panel panel-default">
+  <div class="panel-heading">Groups<span class="badge pull-right"><%=  app.groups.size %></span></div>
+  <ul class="list-group">
+  <% app.groups.each do |group| %>
+  <li class="list-group-item">
+    <span class="label label-default">ID</span> <%= group.id %>
+    <span class="label label-default">Name</span> <%= group.name %>
+    <span class="badge"><%= app.group_users(group.id).size %> users</span>
+  </li>
+  <% end %>
+  </ul>
+</div>
\ No newline at end of file
diff --git a/views/_app_users.erb b/views/_app_users.erb
index 954a0bd..e015009 100644
--- a/views/_app_users.erb
+++ b/views/_app_users.erb
@@ -5,6 +5,7 @@
   <li class="list-group-item clearfix">
     <span class="label label-default">OpenID</span> <span class="text-muted"><%= user.openid %></span>
     <span class="label label-default">Nickname</span> <a class="btn btn-link" data-toggle="modal" href="#user-modal-<%= user.openid %>"><%= user.nickname %></a>
+    <span class="label label-default">Group</span> <%= app.user_group_name(user) %>
   </li>
   <li class="list-group-item">
     <div class="row">
diff --git a/views/app.erb b/views/app.erb
index efbe7ad..10d9233 100644
--- a/views/app.erb
+++ b/views/app.erb
@@ -28,6 +28,7 @@
   </div>
 
   <div class="col-sm-7">
+    <%= erb :_app_groups, locals: {app: app} %>
     <%= erb :_app_users, locals: {app: app} %>
     <%= erb :_app_medias, locals: {app: app} %>
   </div>