changed a command, changed spacing

README.md

@@ -78,14 +78,14 @@ Finally, install these packages from the standard repositories:
 
     You should be installing the latest ansible version which as of time of writing is `ansible 2.1.1.0`. You can verify the version number by running `ansible --version`.
 
-    **MacOS**
+  **MacOS**
 
-    Install virtual box at:  
-    [VirtualBox.org](https://www.virtualbox.org/wiki/Downloads)
+  Install virtual box at:  
+  [VirtualBox.org](https://www.virtualbox.org/wiki/Downloads)
 
-    Then install Vagrant and Ansible with Homebrew with the following command:
-    
-    `brew install Vagrant Ansible`
+  Then install Vagrant and Ansible with Homebrew with the following command:
+
+  `brew install Caskroom/cask/vagrant Ansible`
 
 ## Developing with Vagrant
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