extract workdir from Dockerfile, and skip [[statics]] if workdir cont…

…ains a variable

lib/generators/dockerfile_generator.rb

@@ -1311,9 +1311,11 @@ def fly_make_toml
  end
  end
 
+ # Add statics if not already present and not using a web server and workdir doesn't contain a variable
  unless options.nginx? || using_passenger? || options.thruster? || @gemfile.include?("thruster")
- unless toml.include? "[statics]"
- toml += "[[statics]]\n guest_path = \"/rails/public\"\n url_prefix = \"/\"\n\n"
+ workdir = (IO.read 'Dockerfile' rescue '').scan(/^\s*WORKDIR\s+(\S+)/).flatten.last
+ unless workdir && !workdir.include?('$') && toml.include?("[statics]")
+ toml += "[[statics]]\n guest_path = \"#{workdir}/public\"\n url_prefix = \"/\"\n\n"
  end
  end