Change initialization guide introduction

We will no longer cover every single file that is loaded by Rails, as
this would be too difficult and time consuming to maintain.

We also expect the reader to know about rails server at this point.

guides/source/initialization.textile

@@ -8,14 +8,14 @@ as of Rails 4. It is an extremely in-depth guide and recommended for advanced Ra
 
 endprologue.
 
-This guide goes through every single file, class and method call that is
+This guide goes through every method call that is
 required to boot up the Ruby on Rails stack for a default Rails 4 application, explaining each part in detail along the way. For this guide, we will be focusing on how the two most common methods (+rails server+ and Passenger) boot a Rails application.
 
 NOTE: Paths in this guide are relative to Rails or a Rails application unless otherwise specified.
 
 h3. Launch!
 
-As of Rails 3, +script/server+ has become +rails server+. This was done to centralize all rails related commands to one common file.
+A Rails application is usually started with the command +rails server+.
 
 h4. +bin/rails+