Document installation step with pdm

PDM does not have pip in the virtualenv by default.

The `tailwind init` command will try to install `cookiecutter` automatically. Let's mention that explicitly in the installation steps.

Author: linkdd

docs/installation.md

@@ -37,14 +37,23 @@
    python manage.py tailwind init
    ```
 
+   If you are using [pdm](https://pdm-project.org/), you might need to ensure `pip` is installed in your virtualenv:
+
+   ```bash
+   pdm run python -m ensurepip
+   ```
+
+   See [pdm's documentation](https://pdm-project.org/en/latest/usage/venv/#including-pip-in-your-virtual-environment)
+   for more information.
+
    > Note: By default, we create an app compatible with Tailwind CSS version 4. If you want to create an app compatible
    > with Tailwind CSS version 3, you can use the `--tailwind-version 3` flag:
 
     ```bash
     python manage.py tailwind init --tailwind-version 3
     ```
 
-4. Add your newly created `'theme'` app to `INSTALLED_APPS` in `settings.py`:
+5. Add your newly created `'theme'` app to `INSTALLED_APPS` in `settings.py`:
 
    ```python
    INSTALLED_APPS = [
@@ -54,13 +63,13 @@
    ]
    ```
 
-5. Register the generated `'theme'` app by adding the following line to `settings.py`:
+6. Register the generated `'theme'` app by adding the following line to `settings.py`:
 
    ```python
    TAILWIND_APP_NAME = 'theme'
    ```
 
-6. Install *Tailwind CSS* dependencies by running the following command:
+7. Install *Tailwind CSS* dependencies by running the following command:
 
    ```bash
    python manage.py tailwind install
@@ -72,10 +81,10 @@
     python manage.py tailwind install --no-package-lock
     ```
 
-7. The *Django Tailwind* comes with a simple `base.html` template located at
+8. The *Django Tailwind* comes with a simple `base.html` template located at
    `your_tailwind_app_name/templates/base.html`. You can always extend or delete it if you already have a layout.
 
-8. If you are not using the `base.html` template that comes with *Django Tailwind*, add `{% tailwind_css %}` to
+9. If you are not using the `base.html` template that comes with *Django Tailwind*, add `{% tailwind_css %}` to
    your `base.html` template:
 
    ```html
@@ -90,7 +99,7 @@
 
    The `{% tailwind_css %}` tag includes Tailwind's stylesheet.
 
-9. Let's also add and configure `django_browser_reload`, which takes care of automatic page and CSS refreshes in
+10. Let's also add and configure `django_browser_reload`, which takes care of automatic page and CSS refreshes in
    development mode. Add it to `INSTALLED_APPS` in `settings.py`:
 
     ```python
@@ -102,7 +111,7 @@
     ]
     ```
 
-10. Staying in `settings.py`, add the middleware:
+11. Staying in `settings.py`, add the middleware:
 
     ```python
     MIDDLEWARE = [
@@ -115,7 +124,7 @@
     The middleware should be listed after any that encode the response, such as Django’s `GZipMiddleware`. The
     middleware automatically inserts the required script tag on HTML responses before `</body>` when `DEBUG` is `True`.
 
-11. Include `django_browser_reload` URL in your root `urls.py`:
+12. Include `django_browser_reload` URL in your root `urls.py`:
 
     ```python
     from django.urls import include, path
@@ -125,7 +134,7 @@
     ]
     ```
 
-12. Finally, you should be able to use *Tailwind CSS* classes in HTML. Start the development server by running the
+13. Finally, you should be able to use *Tailwind CSS* classes in HTML. Start the development server by running the
     following command in your terminal:
 
     ```bash