Room names added as unique. An error is now showed if an error occurred while creating a room. Updated backbone and underscore to latest versions

Author: gabceb

app/assets/javascripts/backbone/kandan.js.coffee.erb

@@ -70,6 +70,8 @@ window.Kandan =
   initTabs: ()->
     $('#kandan').tabs({
       select: (event, ui)->
+        if ui.tab.id == "create_channel" then return false
+
         $(document).data('active-channel-id',
           Kandan.Helpers.Channels.getChannelIdByTabIndex(ui.index))
         Kandan.Data.Channels.runCallbacks('change')

app/assets/javascripts/backbone/views/channel_tabs.js.coffee

@@ -32,6 +32,9 @@ class Kandan.Views.ChannelTabs extends Backbone.View
       channel.save({}, {
         success: (model)->
           Kandan.Helpers.Channels.createChannelArea(model)
+
+        error: (model)->
+          alert("Something went wrong while creating a new Room.\n\nMaybe the room name is already taken?")
       })
       console.log "create channel: #{channelName}"
     return false