Use ruby 2.x hash syntax

app/controllers/api/application_controller.rb

@@ -1,6 +1,6 @@
 class API::ApplicationController < ApplicationController
   skip_before_filter :verify_authenticity_token
-  skip_before_filter :authenticate!, :only => [:cor_preflight]
+  skip_before_filter :authenticate!, only: [:cor_preflight]
 
   before_filter :cor_filter
 

app/controllers/api/sessions_controller.rb

@@ -1,11 +1,11 @@
 class API::SessionsController < API::ApplicationController
-  skip_before_filter :authenticate!, :only => [:create]
+  skip_before_filter :authenticate!, only: [:create]
 
   def create
     user = User.find_by_email(params[:session][:email])
 
     if ! user.try(:authenticate?, params[:session][:password])
-      return render :json => '', :status => :not_found
+      return render json: '', status: :not_found
     end
 
     @user = user

app/controllers/api/sounds_controller.rb

@@ -2,6 +2,6 @@ class API::SoundsController < API::ApplicationController
   # FIXME: add some tests!
   def show
     sound = Sound.find params[:id]
-    send_file sound.path, :type => sound.mime_type
+    send_file sound.path, type: sound.mime_type
   end
 end

app/controllers/playlists_controller.rb

@@ -10,9 +10,9 @@ class PlaylistsController < ApplicationController
   def create
     @playlist = current_user.playlists.build(params[:playlist])
     if @playlist.save
-      redirect_to :action => 'index'
+      redirect_to action: 'index'
     else
-      render :action => 'new'
+      render action: 'new'
     end
   end
 
@@ -23,9 +23,9 @@ class PlaylistsController < ApplicationController
   def update
     @playlist = Playlist.find(params[:id])
     if @playlist.update_attributes params[:playlist]
-      redirect_to :action => 'index'
+      redirect_to action: 'index'
     else
-      render :action => 'edit'
+      render action: 'edit'
     end
   end
 end

app/controllers/sessions_controller.rb

@@ -1,5 +1,5 @@
 class SessionsController < ApplicationController
-  skip_before_filter :authenticate!, :only => [:new, :create]
+  skip_before_filter :authenticate!, only: [:new, :create]
 
   def create
     user = User.find_by_email(params[:session][:email])

app/controllers/sounds_controller.rb

@@ -1,6 +1,6 @@
 class SoundsController < ApplicationController
   def show
     sound = Sound.find params[:id]
-    send_file sound.path, :type => sound.mime_type
+    send_file sound.path, type: sound.mime_type
   end
 end

app/controllers/users_controller.rb

@@ -1,5 +1,5 @@
 class UsersController < ApplicationController
-  skip_before_filter :authenticate!, :only => [:new, :create]
+  skip_before_filter :authenticate!, only: [:new, :create]
 
   def new
     @user = User.new