put back missing Compose Wordpress example (docker#4228)

* put back missing Compose Wordpress example

Signed-off-by: Victoria Bialas <victoria.bialas@docker.com>

* addressed review comments, postponing one comment re: yaml code fencing

Signed-off-by: Victoria Bialas <victoria.bialas@docker.com>

compose/wordpress.md

@@ -0,0 +1,147 @@
+---
+description: Getting started with Compose and WordPress
+keywords: documentation, docs,  docker, compose, orchestration, containers
+title: "Quickstart: Compose and WordPress"
+---
+
+You can use Docker Compose to easily run WordPress in an isolated environment
+built with Docker containers. This quick-start guide demonstrates how to use
+Compose to set up and run WordPress. Before starting, you'll need to have
+[Compose installed](/compose/install.md).
+
+### Define the project
+
+1.  Create an empty project directory.
+
+    You can name the directory something easy for you to remember.
+    This directory is the context for your application image. The
+    directory should only contain resources to build that image.
+
+    This project directory will contain a `docker-compose.yml` file which will
+    be complete in itself for a good starter wordpress project.
+
+    >**Tip**: You can use either a `.yml` or `.yaml` extension for
+    this file. They both work.
+
+2.  Change directories into your project directory.
+
+    For example, if you named your directory `my_wordpress`:
+
+        cd my_wordpress/
+
+3.  Create a `docker-compose.yml` file that will start your
+    `WordPress` blog and a separate `MySQL` instance with a volume
+    mount for data persistence:
+
+    ```none
+    version: '3'
+
+    services:
+       db:
+         image: mysql:5.7
+         volumes:
+           - db_data:/var/lib/mysql
+         restart: always
+         environment:
+           MYSQL_ROOT_PASSWORD: somewordpress
+           MYSQL_DATABASE: wordpress
+           MYSQL_USER: wordpress
+           MYSQL_PASSWORD: wordpress
+
+       wordpress:
+         depends_on:
+           - db
+         image: wordpress:latest
+         ports:
+           - "8000:80"
+         restart: always
+         environment:
+           WORDPRESS_DB_HOST: db:3306
+           WORDPRESS_DB_USER: wordpress
+           WORDPRESS_DB_PASSWORD: wordpress
+    volumes:
+        db_data:
+    ```
+
+   > **Notes**:
+   >
+   * The docker volume `db_data` persists any updates made by Wordpress
+   to the database. [Learn more about docker volumes](/engine/tutorials/dockervolumes.md)
+   >
+   * WordPress Multisite works only on ports `80` and `443`.
+   {: .note-vanilla}
+
+### Build the project
+
+Now, run `docker-compose up -d` from your project directory.
+
+This runs [docker-compose up](/compose/reference/up/) in detached mode, pulls
+the needed images, and starts the wordpress and database containers, as shown in
+the example below.
+
+```
+$ docker-compose up -d
+Creating network "my_wordpress_default" with the default driver
+Pulling db (mysql:5.7)...
+5.7: Pulling from library/mysql
+efd26ecc9548: Pull complete
+a3ed95caeb02: Pull complete
+...
+Digest: sha256:34a0aca88e85f2efa5edff1cea77cf5d3147ad93545dbec99cfe705b03c520de
+Status: Downloaded newer image for mysql:5.7
+Pulling wordpress (wordpress:latest)...
+latest: Pulling from library/wordpress
+efd26ecc9548: Already exists
+a3ed95caeb02: Pull complete
+589a9d9a7c64: Pull complete
+...
+Digest: sha256:ed28506ae44d5def89075fd5c01456610cd6c64006addfe5210b8c675881aff6
+Status: Downloaded newer image for wordpress:latest
+Creating my_wordpress_db_1
+Creating my_wordpress_wordpress_1
+```
+
+> **Note**: WordPress Multisite works only on ports `80` and/or `443`.
+If you get an error message about binding `0.0.0.0` to port `80` or `443`
+(depending on which one you specified), it is likely that the port you
+configured for WordPress is already in use by another service.
+
+### Bring up WordPress in a web browser
+
+At this point, WordPress should be running on port `8000` of your Docker Host,
+and you can complete the "famous five-minute installation" as a WordPress
+administrator.
+
+> **Note**: The WordPress site will not be immediately available on port `8000`
+because the containers are still being initialized and may take a couple of
+minutes before the first load.
+
+If you are using [Docker Machine](/machine/index.md), you can run the command
+`docker-machine ip MACHINE_VM` to get the machine address, and then open
+`http://MACHINE_VM_IP:8000` in a web browser.
+
+If you are using Docker for Mac or Docker for Windows, you can use
+`http://localhost` as the IP address, and open `http://localhost:8000` in a web
+browser.
+
+![Choose language for WordPress install](images/wordpress-lang.png)
+
+![WordPress Welcome](images/wordpress-welcome.png)
+
+### Shutdown and cleanup
+
+The command [docker-compose down](/compose/reference/down.md) removes the
+containers and default network, but preserves your Wordpress database.
+
+The command `docker-compose down --volumes` removes the containers, default
+network, and the Wordpress database.
+
+## More Compose documentation
+
+- [User guide](/compose/index.md)
+- [Installing Compose](/compose/install.md)
+- [Getting Started](/compose/gettingstarted.md)
+- [Get started with Django](/compose/django.md)
+- [Get started with Rails](/compose/rails.md)
+- [Command line reference](/compose/reference/index.md)
+- [Compose file reference](/compose/compose-file/index.md)