Save track files in new Sound model:

* Consolidate migrations
* Add Sound model. Each sound can belong to a track and contains
  informations about one sound file.

db/schema.rb

@@ -10,13 +10,13 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20110913195421) do
+ActiveRecord::Schema.define(:version => 20110916003929) do
 
   create_table "playlists", :force => true do |t|
+    t.integer  "user_id"
     t.string   "name"
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.integer  "user_id"
   end
 
   create_table "sessions", :force => true do |t|
@@ -29,19 +29,25 @@ ActiveRecord::Schema.define(:version => 20110913195421) do
   add_index "sessions", ["session_id"], :name => "index_sessions_on_session_id"
   add_index "sessions", ["updated_at"], :name => "index_sessions_on_updated_at"
 
+  create_table "sounds", :force => true do |t|
+    t.integer  "track_id"
+    t.string   "sha256"
+    t.string   "mime_type"
+    t.datetime "created_at"
+    t.datetime "updated_at"
+  end
+
   create_table "tracks", :force => true do |t|
     t.string   "name"
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.string   "mime_type"
-    t.string   "sha256"
   end
 
   create_table "users", :force => true do |t|
     t.string   "email"
+    t.string   "password_hash"
     t.datetime "created_at"
     t.datetime "updated_at"
-    t.string   "password_hash"
   end
 
   add_index "users", ["email"], :name => "index_users_on_email", :unique => true