Update tfb-startup.sh

Fix problem with permissions in startup script

toolset/continuous/tfb-startup.sh

@@ -21,7 +21,9 @@ echo "moving to tfb directory"
 cd $TFB_REPOPARENT/$TFB_REPONAME
 
 echo "building tfb docker image"
-docker build -t techempower/tfb .
+docker build -t techempower/tfb \
+  --build-arg USER_ID=$(id -u) \
+  --build-arg GROUP_ID=$(id -g) .
 
 echo "running tfb docker image"
 docker run \