Use correct casing for Dokku name

lowercase should only be used to refer to the binary, not the project

docs/appendices/0.5.0-migration-guide.md

@@ -1,6 +1,6 @@
 # 0.5.0 Migration Guide
 
-## nginx-vhosts
+## `nginx-vhosts` plugin
 
 - The nginx-vhosts template language is now [sigil](https://github.com/gliderlabs/sigil)
   - No need to escape literal `$` characters (or other "bash-isms")
@@ -8,7 +8,7 @@
   - A detailed list of template variables can be found [here](/dokku/configuration/nginx/#available-template-variables)
 - A custom nginx-vhosts template must be named `nginx.conf.sigil`
   - The default path for this custom template is the root of your repo (i.e. `/app` in the container or `WORKDIR` if defined in a dockerfile app)
-  - Dokku no longer looks for this file in `/home/dokku/myapp` on the dokku server
+  - Dokku no longer looks for this file in `/home/dokku/myapp` on the Dokku server
   - Check out an example template [here](/dokku/configuration/nginx/)
 - Support for server-wide SSL certs have been dropped in favor of using the `certs` plugin
   - `dokku certs:add myapp < certs.tar`