Merge pull request docker#78 from coreygarvey/patch-1

Update docs w/ missing "to"

Author: StefanScherer

docs/tutorial/multi-container-apps/index.md

@@ -37,7 +37,7 @@ For now, we will create the network first and attach the MySQL container at star
     docker network create todo-app
     ```
 
-1. Start a MySQL container and attach it the network. We're also going to define a few environment variables that the
+1. Start a MySQL container and attach it to the network. We're also going to define a few environment variables that the
   database will use to initialize the database (see the "Environment Variables" section in the [MySQL Docker Hub listing](https://hub.docker.com/_/mysql/)).
 
     ```bash