Documentation: custom env variables

docs/configuration-files/env-file.rst

@@ -1021,7 +1021,7 @@ The PHP container itself does not offer any variables, however you can add any k
 variable into the ``.env`` file which will automatically be available to the started PHP container
 and thus in any of your PHP projects.
 
-If your application requires are variable to determine if it is run under development or
+If your application requires a variable to determine if it is run under development or
 production, for example: ``APPLICATION_ENV``, you can just add this to the ``.env`` file:
 
 .. code-block:: bash
@@ -1051,6 +1051,8 @@ This will then output ``development``.
 .. note::
    Add as many custom environment variables as you require.
 
+.. seealso:: :ref:`tutorial_custom_environment_variables`
+
 
 Web server
 ----------

docs/tutorials/custom-environment-variables.rst

@@ -0,0 +1,53 @@
+.. _tutorial_custom_environment_variables:
+
+****************************
+Custom environment variables
+****************************
+
+If your application requires a variable to determine if it is run under development or
+production, you can easily add it and make PHP aware of it.
+
+
+**Table of Contents**
+
+.. contents:: :local:
+
+
+Add custom environment variables
+================================
+
+This is fairly simple. Any variable inside the ``.env`` file is considered an environment variable
+and automatically known to PHP.
+
+If you for example require a variable ``APPLICATION_ENV``, with a value of ``production``, you
+would add the following to the ``.env`` file:
+
+.. code-block:: bash
+   :caption: .env
+   :name: .env
+   :emphasize-lines: 1
+
+   APPLICATION_ENV=production
+
+You need to restart the Devilbox for the changes to take effect.
+
+.. note::
+    There is already a proposed section inside the ``.env`` file at the very bottom
+    to add you custom variables to differentiate them from the Devilbox required variables.
+
+
+Use custom environment variables
+================================
+
+Accessing the above defined environment variable on the PHP side is also fairly simple.
+You can use the PHP's built-in function ``getenv`` to obtain the value:
+
+.. code-block:: php
+   :caption: index.php
+   :name: index.php
+   :emphasize-lines: 3
+
+   <?php
+   // Example use of getenv()
+   echo getenv('APPLICATION_ENV');
+   ?>