Thanks you all,
I fixed the problem by adding this command in render-build.sh
if ! gem list foreman -i --silent; then
echo “Installing foreman…”
gem install foreman
fi
bundle exec rails tailwindcss:watch
my full render-build.sh file
by looking to the ./bin/dev file, i saw the line tailwindcss:watch, so i guess i have to stimulate the build file like this file.
thanks to you all again, especially render community site.