fix invite authentication

app/controllers/application_controller.rb

@@ -80,8 +80,8 @@ class ApplicationController < ActionController::Base
 
   # checks if the current_user is member of given group.
   # if fails the user will redirected to startpage
-  def authenticate_membership_or_admin
-    @group = Group.find(params[:id])
+  def authenticate_membership_or_admin(group_id = params[:id])
+    @group = Group.find(group_id)
     unless @group.member?(@current_user) or @current_user.role_admin?
       redirect_to root_path, alert: I18n.t('application.controller.error_members_only')
     end

app/controllers/invites_controller.rb

@@ -1,13 +1,13 @@
 class InvitesController < ApplicationController
 
-  before_filter :authenticate_membership_or_admin, :only => [:new]
-  #TODO: authorize also for create action.
+  before_filter :authenticate_membership_or_admin_for_invites
   
   def new
     @invite = Invite.new(:user => @current_user, :group => @group)
   end
   
   def create
+    authenticate_membership_or_admin params[:invite][:group_id]
     @invite = Invite.new(params[:invite])
     if @invite.save
       Mailer.invite(@invite).deliver
@@ -23,4 +23,10 @@ class InvitesController < ApplicationController
       render action: :new
     end
   end
+
+  protected
+
+  def authenticate_membership_or_admin_for_invites
+    authenticate_membership_or_admin((params[:invite][:group_id] rescue params[:id]))
+  end
 end