We need to be explicit about pull behavior. (#294)

Use rebase as it's more reliable.  In fact, FF outright fails these
days.

Co-authored-by: Joe Clarke <[email protected]>

Dockerfile

@@ -114,6 +114,7 @@ WORKDIR /
 
 RUN git config --global user.name miroslavKovacPantheon
 RUN git config --global user.email [email protected]
+RUN git config --global pull.rebase true
 
 WORKDIR $VIRTUAL_ENV