corrected typo

Author: jakewmeyer

README.md

@@ -88,6 +88,6 @@ See the [Contribution](https://github.com/r-spacex/SpaceX-API/blob/master/CONTRI
 * All data stored as [MongoDB](https://www.mongodb.com/) documents
 * API is deployed on a [Heroku](https://www.heroku.com/) pipeline with staging and production servers
 * A [Docker](https://hub.docker.com/r/jakewmeyer/spacex-api/) image is avaiable for local development
-```Docker
+```bash
 docker pull jakewmeyer/spacex-api
 ```