[ci skip] modify default host in command line guide

Author: y-yagi

guides/source/command_line.md

@@ -61,7 +61,7 @@ With no further work, `rails server` will run our new shiny Rails app:
 $ cd commandsapp
 $ bin/rails server
 => Booting WEBrick
-=> Rails 4.2.0 application starting in development on http://0.0.0.0:3000
+=> Rails 4.2.0 application starting in development on http://localhost:3000
 => Call with -d to detach
 => Ctrl-C to shutdown server
 [2013-08-07 02:00:01] INFO  WEBrick 1.3.1
@@ -79,7 +79,7 @@ The server can be run on a different port using the `-p` option. The default dev
 $ bin/rails server -e production -p 4000
 ```
 
-The `-b` option binds Rails to the specified IP, by default it is 0.0.0.0. You can run a server as a daemon by passing a `-d` option.
+The `-b` option binds Rails to the specified IP, by default it is localhost. You can run a server as a daemon by passing a `-d` option.
 
 ### `rails generate`