Heroku: Cannot push to heroku due to NoMethodError - ruby-on-rails

Question

I ran git push heroic master and got this long error message(truncated it). If I'm not wrong, this is the main cause of the problem remote: NoMethodError: undefined method 'split' for {}:Hash. How do I solve this problem from the terminal, even though the code runs on local machine. Please inform me if more information is required, and perhaps tell me what's wrong here.
Total 0 (delta 0), reused 0 (delta 0)
remote: Compressing source files... done.
remote: Building source:
remote:
remote: ! Warning: Multiple default buildpacks reported the ability to handle this app. The first buildpack in the list below will be used.
remote: Detected buildpacks: Ruby,Node.js
remote: See https://devcenter.heroku.com/articles/buildpacks#buildpack-detect-order
remote: -----> Ruby app detected
remote: -----> Compiling Ruby/Rails
remote: -----> Using Ruby version: ruby-2.5.3
remote:
remote: ###### WARNING:
remote:
remote: You have the `.bundle/config` file checked into your repositor
remote: It contains local state like the location of the installed bundle
remote: as well as configured git local gems, and other settings that should
remote: not be shared between multiple checkouts of a single repo. Please
remote: remove the `.bundle/` folder from your repo and add it to your `.gitignore` file.
remote: https://devcenter.heroku.com/articles/bundler-configuration
remote:
remote: -----> Installing dependencies using bundler 1.15.2
remote: Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin -j4 --deployment
remote: --- ERROR REPORT TEMPLATE -------------------------------------------------------
remote: # Error Report
remote:
remote: ## Questions
remote:
remote: Please fill out answers to these questions, it'll help us figure out
remote: why things are going wrong.
remote:
remote: - **What did you do?**
remote:
remote: I ran the command `vendor/bundle/ruby/2.5.0/bin/bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin -j4 --deployment --no-clean`
remote:
remote: - **What did you expect to happen?**
remote:
remote: I expected Bundler to...
remote:
remote: - **What happened instead?**
remote:
remote: Instead, what happened was...
remote:
remote: - **Have you tried any solutions posted on similar issues in our issue tracker, stack overflow, or google?**
remote:
remote: I tried...
remote:
remote: - **Have you read our issues document, https://github.com/bundler/bundler/blob/master/doc/contributing/ISSUES.md?**
remote:
remote: ...
remote:
remote: ## Backtrace
remote:
remote: ```
remote: NoMethodError: undefined method `split' for {}:Hash
remote: /tmp/build_571ced5049bd8f6d5aa742e589ae07bf/vendor/bundle/ruby/2.5.0/gems/bundler-1.15.2/lib/bundler/settings.rb:253:in `get_array'
remote: /tmp/build_571ced5049bd8f6d5aa742e589ae07bf/vendor/bundle/ruby/2.5.0/gems/bundler-1.15.2/lib/bundler/settings.rb:179:in `without'
remote: /tmp/build_571ced5049bd8f6d5aa742e589ae07bf/vendor/bundle/ruby/2.5.0/gems/bundler-1.15.2/lib/bundler/cli/install.rb:169:in `normalize_groups'
remote: /tmp/build_571ced5049bd8f6d5aa742e589ae07bf/vendor/bundle/ruby/2.5.0/gems/bundler-1.15.2/lib/bundler/cli/install.rb:24:in `run'
remote: /tmp/build_571ced5049bd8f6d5aa742e589ae07bf/vendor/bundle/ruby/2.5.0/gems/bundler-1.15.2/lib/bundler/cli.rb:186:in `block in install'
remote: /tmp/build_571ced5049bd8f6d5aa742e589ae07bf/vendor/bundle/ruby/2.5.0/gems/bundler-1.15.2/lib/bundler/settings.rb:92:in `temporary'
remote: /tmp/build_571ced5049bd8f6d5aa742e589ae07bf/vendor/bundle/ruby/2.5.0/gems/bundler-1.15.2/lib/bundler/cli.rb:185:in `install'
.bundle/config
---
BUNDLE_WITHOUT: ""

Answer 1

The logs are warning you about that you have .bundle/config checked on your version control.
Remove from your repo and push your changes
rm .bundle/config
rmdir .bundle