docs: clarify usage of docker-based installation

ssh-key addition wasn't previously scoped out.

docs/getting-started/install/docker.md

@@ -3,7 +3,7 @@
 Pull the dokku/dokku image:
 
 ```shell
-docker pull dokku/dokku:v0.17.6
+docker pull dokku/dokku:v0.17.7
 ```
 
 Next, run the image.
@@ -17,16 +17,16 @@ docker run \
   --publish 8443:443 \
   --volume /mount:/mount \
   --volume /var/run/docker.sock:/var/run/docker.sock \
-  dokku/dokku:v0.17.6
+  dokku/dokku:v0.17.7
 ```
 
 Dokku is run with the following options:
 
 - The global hostname is set to `dokku.me` on boot.
 - The container name is dokku.
-- SSH port 22 is exposed on the host as 3022.
-- HTTP port 80 is exposed on the host as 8000.
-- HTTPS port 443 is exposed on the host as 8443.
+- Container SSH port 22 is exposed on the host as 3022.
+- Container HTTP port 80 is exposed on the host as 8000.
+- Container HTTPS port 443 is exposed on the host as 8443.
 - Data within the container is stored on the host within the `/mount` directory.
 - The docker socket is mounted into container
 
@@ -34,14 +34,21 @@ Application repositories, plugin config, and plugin data is persisted to disk wi
 
 To install custom plugins, create a `plugin-list` file in the host's `/mount` directory. The plugins listed herein will be automatically installed by Dokku on container boot. This file should be the following format:
 
-```
+```yaml
 plugin_name: repository_url
 ```
 
 An example for installing the postgres and redis plugins follows:
 
-```shell
+```yaml
 postgres: https://github.com/dokku/dokku-postgres.git
 redis: https://github.com/dokku/dokku-redis.git
 ```
 
+To initialize ssh-keys within the container, use `docker exec` to enter the container and run the appropriate ssh-keys commands.
+
+```shell
+docker exec -it dokku bash
+```
+
+Please see the [user management documentation](/docs/deployment/user-management.md) for more information.