Added location of dev.yml

This should make it easier to know which directory you're supposed to work from. I've thought about putting the command "cd .." in to follow up from the previous steps but I wanted to keep the change small for now.

CONTRIBUTING.rst

@@ -98,7 +98,7 @@ Everything happens in ``master`` branch. Therefore, when submitting Merge Reques
 Working with docker
 ^^^^^^^^^^^^^^^^^^^
 
-In development, we use the docker-compose file named ``dev.yml``, and this is why all our docker-compose commands will look like this::
+In development, we use the docker-compose file named ``dev.yml``, residing in the reel2bits directory, and this is why all our docker-compose commands will look like this::
 
     docker-compose -f dev.yml logs