Add docs on how to patch Drupal VM [ci skip]

Author: oxyc

docs/deployment/composer-dependency.md

@@ -32,3 +32,7 @@ _Note that `drupal_core_path` needs to match your `composer.json` configuration.
 If you placed the `config.yml` file in a subdirectory, tell Drupal VM where by adding the location to your `composer.json`. If not, Drupal VM will look for all configuration files in the root of your project.
 
     composer config extra.drupalvm.config_dir 'vm'
+
+## Patching Drupal VM
+
+If you need to patch something in Drupal VM that you're otherwise unable to configure, you can do so with the help of the `composer-patches` plugin. Read the [documentation on how to create and apply patches](../extending/patching.md).

docs/extending/patching.md

@@ -0,0 +1,36 @@
+If you're using Drupal VM as a Composer dependency and need to patch something that you're otherwise unable to configure, you can do so with the help of the [`composer-patches` plugin](https://github.com/cweagans/composer-patches).
+
+Grab a clone of the Drupal VM version your project is using:
+
+    git clone https://github.com/geerlingguy/drupal-vm.git drupal-vm
+    cd drupal-vm
+    git checkout 5.0.0
+
+Make the changes you need and create a patch using `git diff`:
+
+    git diff --cached > custom-roles.patch
+
+Move this file to your project somewhere, eg. `vm/patches/custom-roles.patch`.
+
+Require the [`composer-patches` plugin](https://github.com/cweagans/composer-patches) as a dependency to your project unless you already have it:
+
+    composer require cweagans/composer-patches
+
+Add the patch to the `extra`-field in your `composer.json`:
+
+    {
+      "extra": {
+        "patches": {
+          "geerlingguy/drupal-vm": {
+            "Include custom Drupal VM roles": "vm/patches/custom-roles.patch"
+          }
+        }
+      }
+    }
+
+Re-install the Drupal VM package to apply the patch:
+
+    composer remove --dev geerlingguy/drupal-vm
+    composer require --dev geerlingguy/drupal-vm:5.0.0
+
+Your Drupal VM version is now been patched!

mkdocs.yml

@@ -64,6 +64,7 @@ pages:
     - 'Adding Vagrant plugins Vagrantfile.local': 'extending/vagrantfile.md'
     - 'Passing on CLI arguments to ansible': 'extending/ansible-args.md'
     - 'Pre- and Post-Provision Scripts': 'extending/scripts.md'
+    - 'Patching Drupal VM': 'extending/patching.md'
   - Other Information:
     - 'Networking Notes': 'other/networking.md'
     - 'Vagrant and VirtualBox': 'other/vagrant-virtualbox.md'