Building Redis from example fails with /usr/bin/start-redis-server.sh: not found

Running from this example: https://github.com/fly-apps/redis/

I can’t even get the dockerfile to work locally. The app builds just fine, showing me it copies the right files to the right place, but it continues to error with:

redis   | /bin/sh: /usr/bin/start-redis-server.sh: not found
metrics | signal: interrupt

I’m sure the file is there, when I run

WORKDIR /usr/bin/
ADD file.txt .
RUN pwd
RUN ls

I see

#15 [11/15] RUN pwd
#15 sha256:d91925043c9e2e384740cc78b95ace74df1f41299f4d897c830dc14c67e817ff
#15 0.463 /usr/bin
#15 DONE 0.6s

And

#16 [12/15] RUN ls
#16 sha256:de3e5e76ca1b567caf04299d01913d636ee62a829c047f06df9ea6a981852503
#16 0.637 [
#16 0.637 [[
#16 0.637 awk
#16 0.637 basename
#16 0.637 bc
#16 0.637 beep
...
#16 0.637 start-redis-server.sh

Building from windows if that makes a difference, very curious what’s going on!