Don't use an image to show the results of docker ps

The alternative text of the image was useless, and we were depending on
an external server in order to display it. Furthermore, the text inside
the image was pretty small.

So we're displaying the output of the command as plain text.

docs/en/installation/docker.md

@@ -89,7 +89,12 @@ docker ps
 ```
 
 You should see an output similar to this:
-![docker ps](https://i.imgur.com/ASvzXrd.png)
+
+```bash
+CONTAINER ID   IMAGE                 COMMAND                  CREATED          STATUS          PORTS      NAMES
+603ec83b78a6   consuldemocracy-app   "./docker-entrypoint…"   23 seconds ago   Up 22 seconds              consuldemocracy-app-run-afb6d68e2d99
+d57fdd9637d6   postgres:13.16        "docker-entrypoint.s…"   50 minutes ago   Up 22 seconds   5432/tcp   consuldemocracy-database-1
+```
 
 ## Troubleshooting