rails s　NameError発生

スクールで勉強している未経験者です
rails s で起動しようとすると以下のエラーが出ます

undefined local variable or method `config' for main:Object (NameError)

について調べて見るとGemについてのエラーではないかと予測します

Herokuでデプロイしようとhttps://qiita.com/kazukimatsumoto/items/a0daa7281a3948701c39を参考にGemをいじったりしていました
git reset --hard　でエラー前に戻しても解決されません
ご教授願います

Traceback (most recent call last):
	20: from bin/rails:3:in `<main>'
	19: from bin/rails:3:in `load'
	18: from /Users/katoukento/Desktop/MyApri2/bin/spring:15:in `<top (required)>'
	17: from /Users/katoukento/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
	16: from /Users/katoukento/.rbenv/versions/2.5.1/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
	15: from /Users/katoukento/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.1.0/lib/spring/binstub.rb:11:in `<top (required)>'
	14: from /Users/katoukento/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.1.0/lib/spring/binstub.rb:11:in `load'
	13: from /Users/katoukento/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.1.0/bin/spring:49:in `<top (required)>'
	12: from /Users/katoukento/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.1.0/lib/spring/client.rb:30:in `run'
	11: from /Users/katoukento/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.1.0/lib/spring/client/command.rb:7:in `call'
	10: from /Users/katoukento/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.1.0/lib/spring/client/rails.rb:28:in `call'
	 9: from /Users/katoukento/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.1.0/lib/spring/client/rails.rb:28:in `load'
	 8: from /Users/katoukento/Desktop/MyApri2/bin/rails:9:in `<top (required)>'
	 7: from /Users/katoukento/Desktop/MyApri2/bin/rails:9:in `require'
	 6: from /Users/katoukento/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.0.7.2/lib/rails/commands.rb:18:in `<top (required)>'
	 5: from /Users/katoukento/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.0.7.2/lib/rails/commands/commands_tasks.rb:49:in `run_command!'
	 4: from /Users/katoukento/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.0.7.2/lib/rails/commands/commands_tasks.rb:85:in `server'
	 3: from /Users/katoukento/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.0.7.2/lib/rails/commands/commands_tasks.rb:85:in `tap'
	 2: from /Users/katoukento/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.0.7.2/lib/rails/commands/commands_tasks.rb:88:in `block in server'
	 1: from /Users/katoukento/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.0.7.2/lib/rails/commands/commands_tasks.rb:88:in `require'
/Users/katoukento/Desktop/MyApri2/config/application.rb:8:in `<top (required)>': undefined local variable or method `config' for main:Object (NameError)