build error: per

[JadeVane]

Thanks for developing this amazing project, that's what i need. but I got some error and need help.

Got the error below after running make prod

cd frontend && make prod
make[1]: Entering directory '/home/wenjinyu/Documents/commentoplusplus/frontend'
yarn install
yarn install v1.22.19
[1/4] Resolving packages...
success Already up-to-date.
Done in 0.24s.
node_modules/.bin/gulp prod
make[1]: node_modules/.bin/gulp: Permission denied
make[1]: *** [Makefile:10: prod] Error 127
make[1]: Leaving directory '/home/wenjinyu/Documents/commentoplusplus/frontend'
make: *** [Makefile:42: frontend] Error 2

what's wrong with gulp? I tried npm install gulp but no luck.