Unable to push my rails app to heroku, says there's a gemfile error

Question

I'm a newbie, trying to push my rails application to heroku but it says push rejected.

I've looked at some similar issues on stackoverflow but none of the solutions seem to resolve it for me.

Here's the code from the terminal

Counting objects: 234, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (200/200), done.
Writing objects: 100% (234/234), 393.61 KiB | 0 bytes/s, done.
Total 234 (delta 37), reused 0 (delta 0)
remote: Compressing source files... done.
remote: Building source:
remote:
remote: -----> Ruby app detected
remote: -----> Compiling Ruby/Rails
remote:
remote:  !
remote:  !     There was an error parsing your Gemfile, we cannot continue
remote:  !     /app/tmp/buildpacks/b7af5642714be4eddaa5f35e2b4c36176b839b4abcd9bfe57ee71c358d71152b4fd2cf925c5b6e6816adee359c4f0f966b663a7f8649b0729509d510091abc07/vendor/ruby/heroku-18/lib/ruby/2.5.0/rubygems.rb:289:in `find_spec_for_exe': can't find gem bundler (>= 0.a) with executable bundle (Gem::GemNotFoundException)
remote:  !     from /app/tmp/buildpacks/b7af5642714be4eddaa5f35e2b4c36176b839b4abcd9bfe57ee71c358d71152b4fd2cf925c5b6e6816adee359c4f0f966b663a7f8649b0729509d510091abc07/vendor/ruby/heroku-18/lib/ruby/2.5.0/rubygems.rb:308:in `activate_bin_path'
remote:  !     from /tmp/d20190419-87-z1jfer/bundler-2.0.1/bin/bundle:23:in `<main>'
remote:  !
remote:  !     Push rejected, failed to compile Ruby app.
remote:
remote:  !     Push failed
remote: Verifying deploy...
remote:
remote: !       Push rejected to london-learning.
remote:
To https://git.heroku.com/london-learning.git
 ! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'https://git.heroku.com/london-learning.git'

And this is my Gemfile

source 'https://rubygems.org'
ruby '2.4.4'

gem 'bootsnap', require: false
gem 'devise'
gem 'jbuilder', '~> 2.0'
gem 'pg', '~> 0.21'
gem 'puma'
gem 'rails', '5.2.1'
gem 'redis'

gem 'autoprefixer-rails'
gem 'font-awesome-sass', '~> 5.6.1'
gem 'sassc-rails'
gem 'simple_form'
gem 'uglifier'
gem 'webpacker'

group :development do
  gem 'web-console', '>= 3.3.0'
end

group :development, :test do
  gem 'pry-byebug'
  gem 'pry-rails'
  gem 'listen', '~> 3.0.5'
  gem 'spring'
  gem 'spring-watcher-listen', '~> 2.0.0'
  gem 'dotenv-rails'
end

Any help at all would be greatly appreciated. Thanks!

Answer 1

Try manually install bundler

gem install bundler -v 1.17.3
bundle _1.17.3_ install
git commit -am "Bundler 1.17.3 was installed"
git push heroku master