Deprecated usher file mounting

usher static files

# I'm using this

base = File.expand_path(File.join(File.dirname(__FILE__)))
app = Rack::File.new(base)

routes = Usher::Interface.for(:rack) do
  add("/static/(js|css|img)/:file").to(app)
end

# It would be nice to use this.  I made the paths different 
# to illustrate the need to strip off the first part of the 
# path info before sending to Rack::File.  I've avoided that
# in my current solution.
routes = Usher::Interface.for(:rack) do
  add_static("/static1").from("/static2")
end