fix tailwindcss-rails support on Windows

[espinosa]

Hi,
I try to support this gem on Windows plateform.
I have detected 2 problems:

1. bin/dev is a linux shell command
   I suggest to add a new file named bin/dev.bat

@echo off

set gem_installed=

for /f "delims=" %%a in ('gem list foreman -i') do @set gem_installed=%%a

if %gem_installed%==false (
  echo "Installing foreman..."
  gem install foreman
)

foreman start -f Procfile.dev %*

2. command bin/rails in Procfile.dev is not recognized
   Replace bin/rails by ruby bin/rails
   I suggest to create a file named Procfile.dev.windows and copy this file only if windows platform.
   Problem: I don't have found where the copy of files are done.
   Can somebody help me ?
   After this I can submit a pull request.
   Best regards.

[espinosa]

I have found where the copies are done. I will submit a pull request soon.