このチュートリアルに従っていますが、アプリケーションが Heroku にプッシュできません。プッシュしようとしたときに得られる出力は次のとおりです。
-----> Writing config/database.yml to read from DATABASE_URL
-----> Preparing app for Rails asset pipeline
Running: rake assets:precompile
rake aborted!
no implicit conversion of String into Hash
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.13/lib/action_dispat
ch/routing/mapper.rb:254:in `merge'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.13/lib/action_dispat
ch/routing/mapper.rb:254:in `root'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.13/lib/action_dispat
ch/routing/mapper.rb:1321:in `root'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/config/routes.rb:54:in `block in <top (required)>'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.13/lib/action_dispat
ch/routing/route_set.rb:289:in `instance_exec'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.13/lib/action_dispat
ch/routing/route_set.rb:289:in `eval_block'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.13/lib/action_dispat
ch/routing/route_set.rb:267:in `draw'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/config/routes.rb:1:in `<top (required)>'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/activesupport-3.2.13/lib/active_sup
port/dependencies.rb:245:in `load'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/activesupport-3.2.13/lib/active_sup
port/dependencies.rb:245:in `block in load'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/activesupport-3.2.13/lib/active_sup
port/dependencies.rb:236:in `load_dependency'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/activesupport-3.2.13/lib/active_sup
port/dependencies.rb:245:in `load'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/applicati
on/routes_reloader.rb:40:in `block in load_paths'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/applicati
on/routes_reloader.rb:40:in `each'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/applicati
on/routes_reloader.rb:40:in `load_paths'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/applicati
on/routes_reloader.rb:16:in `reload!'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/applicati
on/routes_reloader.rb:26:in `block in updater'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/activesupport-3.2.13/lib/active_sup
port/file_update_checker.rb:78:in `call'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/activesupport-3.2.13/lib/active_sup
port/file_update_checker.rb:78:in `execute'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/applicati
on/routes_reloader.rb:27:in `updater'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/applicati
on/routes_reloader.rb:7:in `execute_if_updated'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/applicati
on/finisher.rb:66:in `block in <module:Finisher>'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/initializ
able.rb:30:in `instance_exec'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/initializ
able.rb:30:in `run'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/initializ
able.rb:55:in `block in run_initializers'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/initializ
able.rb:54:in `each'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/initializ
able.rb:54:in `run_initializers'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/applicati
on.rb:136:in `initialize!'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/railtie/c
onfigurable.rb:30:in `method_missing'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/config/environment.rb:5:in `<top (required)>'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/applicati
on.rb:103:in `require'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/applicati
on.rb:103:in `require_environment!'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/railties-3.2.13/lib/rails/applicati
on.rb:297:in `block (2 levels) in initialize_tasks'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.13/lib/sprockets/ass
ets.rake:93:in `block (2 levels) in <top (required)>'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.13/lib/sprockets/ass
ets.rake:60:in `block (3 levels) in <top (required)>'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.13/lib/sprockets/ass
ets.rake:23:in `invoke_or_reboot_rake_task'
/tmp/build_4b2bc135-54ea-4d31-a9f3-7a58601a5aa6/vendor/bundle/ruby/2.0.0/gems/actionpack-3.2.13/lib/sprockets/ass
ets.rake:29:in `block (2 levels) in <top (required)>'
Tasks: TOP => environment
(See full trace by running task with --trace)
!
! Precompiling assets failed.
!
! Push rejected, failed to compile Ruby app
To git@heroku.com:fast-plains-3333.git
! [remote rejected] master -> master (pre-receive hook declined)
編集：
Here is my environment.rb
# Load the rails application
require File.expand_path('../application', __FILE__)
# Initialize the rails application
TestApp::Application.initialize!