`rake assets:precompile` not resolving

Maybe I'm doing this wrong? Starting with no dependencies and running `rake assets:precompile` I get an error for a missing dependency. Looking at the trace, it doesn't seem like `bower:install` is ever called.

```
** Invoke assets:precompile (first_time)
** Execute assets:precompile
/Users/nic/.rvm/rubies/ruby-2.0.0-p353/bin/ruby /Users/nic/.rvm/gems/ruby-2.0.0-p353@zeumo/bin/rake assets:precompile:all RAILS_ENV=production RAILS_GROUPS=assets --trace
** Invoke assets:precompile:all (first_time)
** Execute assets:precompile:all
** Invoke assets:precompile:primary (first_time)
** Invoke assets:environment (first_time)
** Execute assets:environment
** Invoke tmp:cache:clear (first_time)
** Execute tmp:cache:clear
** Execute assets:precompile:primary
...
```

``` ruby
# config/initializers/bower_rails.rb
BowerRails.configure do |bower_rails|
  bower_rails.resolve_before_precompile = true
end
```

What am I missing?