docker unable to find/read lockfile

[k_ut]

I have a small shiny web app and I uploaded it after taking "packrat::snapshot()" and bundling it "packrat::bundle(include.bundles = FALSE, omit.cran.src = TRUE) ". but after uploading when when docker calls "packrat::restore()", it is not able to find the packrat.lock file even though it is there. following is the error 

"91mError: This project does not have a lockfile. (Have you called 'packrat::snapshot()' yet?)
Execution halted
0mThe command '/bin/sh -c su docker -c "R -e 'packrat::restore();'"' returned a non-zero code: 1".

Pls let me know if someone knows why this might be happening or any extra information 

Note: I will not be able to use "renv" and can use "packrat" only for it.