Added docker troubleshooting info to README

This adds some troubleshooting information for people that are using docker for their rails instances.

Co-authored-by: Mike Dalessio <mike.dalessio@gmail.com>

Author: venarius

README.md

@@ -26,6 +26,7 @@
   * [Rails Engines support (Experimental)](#rails-engines-support-experimental)
 - [Troubleshooting](#troubleshooting)
   * [The `watch` command is hanging](#the-watch-command-is-hanging)
+  * [The `build` command (or `bin/rails assets:precompile`) is hanging inside a docker container](#the-build-command-or-binrails-assetsprecompile-is-hanging-inside-a-docker-container)
   * [Lost keystrokes or hanging when using terminal-based debugging tools (e.g. IRB, Pry, `ruby/debug`...etc.) with the Puma plugin](#lost-keystrokes-or-hanging-when-using-terminal-based-debugging-tools-eg-irb-pry-rubydebugetc-with-the-puma-plugin)
   * [Running in a docker container exits prematurely](#running-in-a-docker-container-exits-prematurely)
   * [Conflict with sassc-rails](#conflict-with-sassc-rails)
@@ -428,6 +429,10 @@ There is a [known issue](https://github.com/tailwindlabs/tailwindcss/issues/1724
 
 Please try uninstalling `watchman` and try running the watch task again.
 
+### The `build` command (or `bin/rails assets:precompile`) is hanging inside a docker container
+
+Without a `WORKDIR`, tailwind may search the entire filesystem for files with CSS class names. So, please make sure your Dockerfile uses a `WORKDIR`.
+
 ### Lost keystrokes or hanging when using terminal-based debugging tools (e.g. IRB, Pry, `ruby/debug`...etc.) with the Puma plugin
 
 We've addressed the issue and you can avoid the problem by upgrading `tailwindcss-rails` to [v2.4.1](https://github.com/rails/tailwindcss-rails/releases/tag/v2.4.1) or later versions.