Typo in custom base box page

usage/custom_box.md

@@ -9,6 +9,6 @@ The following describes how to setup the Vagrant box so that it can be used inst
 - If you want to use this custom box for the project you are currently running then you'll need to make sure you have deleted the existing box. Run `vagrant destroy` to destroy the current virtual machine.
 - Add the variable `vlad_custom_base_box_name` to your settings file to let Vlad know that you want to use this box to set the virtual machine up with. This only needs to be the name of the box as Vagrant already knows where to find it.
 ```vlad_custom_base_box_name : "name_of_box"```
-- Now run `vagrant up` to boot and provision your virtual machine using the custom box as a starting point. Vlad will still run the Ansible provisioning step but this will mainly to verify the configuration.
+- Now run `vagrant up` to boot and provision your virtual machine using the custom box as a starting point. Vlad will still run the Ansible provisioning step but this will be mainly to verify the configuration.
 
 Once you have your custom base box you can give it to other members of your team. They'll need to run the `vagrant box add name_of_box /path/to/package.box` command but once done they will have the same setup as you and will be able to start working once they have launched the box. Although the provisioning step does run when the box launches it will only verify the configuration and as such will only take a fraction of the time than a normal Vlad provisioning run takes.