herokuにrailsページをデプロイできない

Question

どなたか教えてください。

cloud9からherokuにデプロイしようと思ったのですが、リリースされず。
Build Logを見た所、

   rake aborted!
   NoMethodError: undefined method `[]' for nil:NilClass

が理由のようだったので、
こちら（http://qiita.com/pokohide/items/017afa5be3b7dc200a8d#nomethoderror-undefined-method-for-nilnilclass）に基づいて、application.css.scssと名前を変えてみたのですが、失敗したままでした。
どなたか対処方法のアドバイスをいただけないでしょうか？
よろしくお願いいたします。

念のためにBuild Logを追記させていただきます↓

-----> Ruby app detected
-----> Compiling Ruby/Rails
-----> Using Ruby version: ruby-2.3.4
-----> Installing dependencies using bundler 1.15.1
       Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin -j4 --deployment
       Fetching gem metadata from https://rubygems.org/.........
       Fetching version metadata from https://rubygems.org/..
       Fetching dependency metadata from https://rubygems.org/.
       Fetching rake 12.0.0
       Fetching concurrent-ruby 1.0.5
       Fetching i18n 0.8.5
       Installing i18n 0.8.5
       Installing rake 12.0.0
       Installing concurrent-ruby 1.0.5
       Fetching minitest 5.10.2
       Fetching thread_safe 0.3.6
       Installing minitest 5.10.2
       Installing thread_safe 0.3.6
       Fetching builder 3.2.3
       Fetching erubis 2.7.0
       Installing builder 3.2.3
       Installing erubis 2.7.0
       Fetching mini_portile2 2.2.0
       Fetching rack 2.0.3
       Installing mini_portile2 2.2.0
       Fetching nio4r 2.1.0
       Installing rack 2.0.3
       Installing nio4r 2.1.0 with native extensions
       Fetching websocket-extensions 0.1.2
       Fetching mime-types-data 3.2016.0521
       Installing websocket-extensions 0.1.2
       Fetching arel 7.1.4
       Installing mime-types-data 3.2016.0521
       Installing arel 7.1.4
       Fetching method_source 0.8.2
       Installing method_source 0.8.2
       Fetching thor 0.19.4
       Using bundler 1.15.1
       Fetching execjs 2.7.0
       Installing thor 0.19.4
       Installing execjs 2.7.0
       Fetching sass 3.4.25
       Fetching puma 3.9.1
       Installing puma 3.9.1 with native extensions
       Installing sass 3.4.25
       Fetching tilt 2.0.7
       Installing tilt 2.0.7
       Fetching coffee-script-source 1.12.2
       Installing coffee-script-source 1.12.2
       Fetching turbolinks-source 5.0.3
       Installing turbolinks-source 5.0.3
       Fetching multi_json 1.12.1
       Installing multi_json 1.12.1
       Fetching pg 0.20.0
       Installing pg 0.20.0 with native extensions
       Fetching tzinfo 1.2.3
       Installing tzinfo 1.2.3
       Fetching nokogiri 1.8.0
       Installing nokogiri 1.8.0 with native extensions
       Fetching rack-test 0.6.3
       Installing rack-test 0.6.3
       Fetching sprockets 3.7.1
       Installing sprockets 3.7.1
       Fetching websocket-driver 0.6.5
       Installing websocket-driver 0.6.5 with native extensions
       Fetching mime-types 3.1
       Installing mime-types 3.1
       Fetching autoprefixer-rails 7.1.2
       Installing autoprefixer-rails 7.1.2
       Fetching uglifier 3.2.0
       Installing uglifier 3.2.0
       Fetching coffee-script 2.4.1
       Installing coffee-script 2.4.1
       Fetching turbolinks 5.0.1
       Installing turbolinks 5.0.1
       Fetching activesupport 5.0.3
       Installing activesupport 5.0.3
       Fetching mail 2.6.6
       Installing mail 2.6.6
       Fetching bootstrap-sass 3.3.7
       Installing bootstrap-sass 3.3.7
       Fetching globalid 0.4.0
       Installing globalid 0.4.0
       Fetching activemodel 5.0.3
       Installing activemodel 5.0.3
       Fetching jbuilder 2.6.4
       Installing jbuilder 2.6.4
       Fetching activejob 5.0.3
       Installing activejob 5.0.3
       Fetching activerecord 5.0.3
       Installing activerecord 5.0.3
       Fetching rails-dom-testing 2.0.3
       Fetching loofah 2.0.3
       Installing loofah 2.0.3
       Installing rails-dom-testing 2.0.3
       Fetching rails-html-sanitizer 1.0.3
       Installing rails-html-sanitizer 1.0.3
       Fetching actionview 5.0.3
       Installing actionview 5.0.3
       Fetching actionpack 5.0.3
       Installing actionpack 5.0.3
       Fetching actionmailer 5.0.3
       Fetching actioncable 5.0.3
       Fetching railties 5.0.3
       Installing actionmailer 5.0.3
       Installing actioncable 5.0.3
       Fetching sprockets-rails 3.2.0
       Installing railties 5.0.3
       Installing sprockets-rails 3.2.0
       Fetching rails 5.0.3
       Fetching sass-rails 5.0.6
       Fetching coffee-rails 4.2.2
       Installing rails 5.0.3
       Installing sass-rails 5.0.6
       Installing coffee-rails 4.2.2
       Fetching jquery-rails 4.3.1
       Installing jquery-rails 4.3.1
       Bundle complete! 17 Gemfile dependencies, 55 gems now installed.
       Gems in the groups development and test were not installed.
       Bundled gems are installed into ./vendor/bundle.
       Bundle completed (23.49s)
       Cleaning up the bundler cache.
-----> Installing node-v6.10.0-linux-x64
-----> Detecting rake tasks
-----> Preparing app for Rails asset pipeline
       Running: rake assets:precompile
       I, [2017-07-08T14:07:32.543834 #1345]  INFO -- : Writing /tmp/build_a80d16e284cf0e22593b620c7ea07b1a/public/assets/application-731eb6bd5d68d47eb9b931e7f005a458f11d76b23a517cc0bd892977bc948817.js
       I, [2017-07-08T14:07:32.544766 #1345]  INFO -- : Writing /tmp/build_a80d16e284cf0e22593b620c7ea07b1a/public/assets/application-731eb6bd5d68d47eb9b931e7f005a458f11d76b23a517cc0bd892977bc948817.js.gz
       rake aborted!
       NoMethodError: undefined method `[]' for nil:NilClass
       /tmp/build_a80d16e284cf0e22593b620c7ea07b1a/vendor/bundle/ruby/2.3.0/gems/sprockets-3.7.1/lib/sprockets/sass_processor.rb:278:in `sprockets_context'
       /tmp/build_a80d16e284cf0e22593b620c7ea07b1a/vendor/bundle/ruby/2.3.0/gems/sprockets-3.7.1/lib/sprockets/sass_processor.rb:124:in `asset_path'
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             /tmp/build_a80d16e284cf0e22593b620c7ea07b1a/vendor/bundle/ruby/2.3.0/gems/rake-12.0.0/exe/rake:27:in `<top (required)>'
       Tasks: TOP => assets:precompile
       (See full trace by running task with --trace)
 !
 !     Precompiling assets failed.
 !
 !     Push rejected, failed to compile Ruby app.
 !     Push failed