title: "require_tree argument must be a directory" rails 3.1.1 precompile assets
body: <p>I've been round and round here with trying to get the assets to pre-compile on my production server (straightforward ubuntu install with ruby 1.9.2 and Rails 3.1.1, and tried 3.1.2RC with the new sprockets 2.10 as well). </p>
  
  <p>"require_tree argument must be a directory".  I've seen other issues related to this on stack but the situation isn't exactly the same and none of the proposed solutions have helped – like create a stub file in the sub folder, then reference only relatively at that point.  No luck.   </p>
  
  <p>And to top it off, of course this works perfectly on all development machines (mac's but with identical configs, even matching gem for gem), in production env.</p>
  
  <p>Here is my /app/assets/javascript/application.js:</p>
  
  <pre><code>//= require ../../views/app/manifest
  //= require_self
  </code></pre>
  
  <p>Not much to it.   Basically just pointing to the real manifest file for the app area (yeah, not exactly boxed vanilla Rails but...)</p>
  
  <p>Here is my stub manifest in my views/admin (/views/app/manifest.coffee.js):</p>
  
  <pre><code># = require ./app
  # = require_tree ./models
  # = require_directory ./views &lt;- or using require_directory, either would work fine.
  </code></pre>
  
  <p>Like I said, in dev env, no issues at all.  The asset pipeline compiles on the fly and everything is great.   Running, rake assets:precompile on the dev machine, no issues either.</p>
  
  <p>I send it up to the production machine and run the exact same code and I get:</p>
  
  <blockquote>
    <p>require_tree argument must be a directory</p>
  </blockquote>
  
  <p>There has to be some tiny tiny difference here that I'm just not seeing.  Any help would be much appreciated!</p>