Add git clone step to build instructions (#130)

Author: gsovereignty

tutorial/build-run.md

@@ -16,6 +16,11 @@ source ~/.bash_profile
 ```
 
 Now, you can install and run the application.
+```
+# Clone the source of the tutorial repository
+git clone https://github.com/cosmos/sdk-application-tutorial.git
+cd sdk-application-tutorial
+```
 
 ```bash
 # Install the app into your $GOBIN