Use new "strong parameters" from rails4

app/controllers/playlists_controller.rb

@@ -8,7 +8,7 @@ class PlaylistsController < ApplicationController
   end
 
   def create
-    @playlist = current_user.playlists.build(params[:playlist])
+    @playlist = current_user.playlists.build(playlist_params)
     if @playlist.save
       redirect_to action: 'index'
     else
@@ -22,10 +22,16 @@ class PlaylistsController < ApplicationController
 
   def update
     @playlist = Playlist.find(params[:id])
-    if @playlist.update_attributes params[:playlist]
+    if @playlist.update_attributes playlist_params
       redirect_to action: 'index'
     else
       render action: 'edit'
     end
   end
+
+  private
+
+  def playlist_params
+    params.require(:playlist).permit(:name)
+  end
 end