Add additional recovery step when running into platform related issues. (rails#122)

* Add additional recovery step instructions.

* Update instructions.

* Add link to additional information.

Author: andrewculver

exe/tailwindcss

@@ -32,6 +32,11 @@ if exe_path.nil?
       bundle install
 
     See `bundle lock --help` output for details.
+        
+    If you're still seeing this message after taking those steps, try running
+    `bundle config` and ensure `force_ruby_platform` isn't set to `true`. See
+    https://github.com/rails/tailwindcss-rails#check-bundle_force_ruby_platform
+    for more details.
   ERRMSG
   exit 1
 end