title: Rails Assets Precompile just not working
body: <p>I've pushed a Rails app to Heroku and keep on running into the following problem:</p>
  
  <p>I'll save changes to my main css.scss file (in assets/stylesheets) or to images in assets/images, push to git, push that to heroku, and reload the page, only to find out that these assets haven't been loaded at all. </p>
  
  <p>This was also a slight problem on the local server, but entering:</p>
  
  <pre><code>rake assets:precompile
  </code></pre>
  
  <p>and reloading the local server usually worked, whereas doing</p>
  
  <pre><code>heroku run rake assets:precompile
  </code></pre>
  
  <p>and then re-pushing does nothing. I've fished around for info and haven't found anything particularly helpful.</p>
  
  <p>Of note, in my <strong>config/application.rb</strong> (some of these the result of said fishing around):</p>
  
  <pre><code># Enable the asset pipeline
  config.assets.enabled = true
  
  if defined?(Bundler)
    # If you precompile assets before deploying to production, use this line
    Bundler.require(*Rails.groups(:assets =&gt; %w(development test)))
    # If you want your assets lazily compiled in production, use this line
    # Bundler.require(:default, :assets, Rails.env)
  end
  </code></pre>
  
  <p>in <strong>config/environments/production.rb</strong>:</p>
  
  <pre><code># Disable Rails's static asset server (Apache or nginx will already do this)
  config.serve_static_assets = false
  
  # Compress JavaScripts and CSS
  config.assets.compress = true
  
  # Fallback to assets pipeline if a precompiled asset is missed
  config.assets.compile = true
  
  # Generate digests for assets URLs
  config.assets.digest = true
  </code></pre>
  
  <p>Of additional possible interest, when I push to heroku, it says, among other things, this:</p>
  
  <pre><code>Preparing app for Rails asset pipeline
         Detected manifest.yml, assuming assets were compiled locally
  -----&gt; Rails plugin injection
         Injecting rails_log_stdout
         Injecting rails3_serve_static_assets
  </code></pre>
  
  <p>and</p>
  
  <pre><code>Installing dependencies using Bundler version 1.3.0.pre.5
  Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin --deployment
  </code></pre>
  
  <p>I learned with Rails 3 and don't really know how the assets pipeline differs from what was available in previous version, so sorry if I'm being an idiot and putting overlapping and/or contradictory settings in my config files. </p>
  
  <p>Would appreciate any help. This has been a headache.</p>