Fix coding standards in application files

app/models/sound.rb

@@ -10,7 +10,7 @@ class Sound < ActiveRecord::Base
     "#{Rails.configuration.sounds_path}/#{sha256}"
   end
 
-  def file=(file)
+  def file= file
     self.sha256 = Digest::SHA256.file(file.path).hexdigest
     FileUtils.cp file.path, path
     self.mime_type = file.content_type

app/models/track.rb

@@ -3,8 +3,8 @@ class Track < ActiveRecord::Base
 
   validates_presence_of :name
 
-  def file=(file)
-    sounds.build(file: file)
+  def file= file
+    sounds.build file: file
   end
 
   def sound

app/models/user.rb

@@ -15,12 +15,12 @@ class User < ActiveRecord::Base
     confirmation: true
   validates_presence_of :password_hash
 
-  def password=(plain_password)
+  def password= plain_password
     @password = plain_password
     self.password_hash = Password.create(plain_password)
   end
 
-  def authenticate?(password)
+  def authenticate? password
     Password.new(password_hash) == password
   end
 end