I am working on a jekyll site for my portfolio, using github, travis-ci.After a long time I wanted to change the content of my site. After making a commit to master branch triggered the build in travis but failed with same error. I tried changing versions of ruby versions but got no luck.
Error
 bundle install --jobs=3 --retry=3 --deployment --path=${BUNDLE_PATH:-vendor/bundle}
168/home/travis/.rvm/rubies/ruby-2.5.1/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)
169 from /home/travis/.rvm/rubies/ruby-2.5.1/lib/ruby/2.5.0/rubygems.rb:308:in `activate_bin_path'
170 from /home/travis/.rvm/gems/ruby-2.5.1/bin/bundle:23:in `<main>'
171 from /home/travis/.rvm/gems/ruby-2.5.1/bin/ruby_executable_hooks:15:in `eval'
172 from /home/travis/.rvm/gems/ruby-2.5.1/bin/ruby_executable_hooks:15:in `<main>'
173
174
travis.yml
language: ruby
rvm:
  - 2.5.1
before_script:
- chmod +x ./script/cibuild
script: ./script/cibuild
cache: bundler
env:
   global:
   - NOKOGIRI_USE_SYSTEM_LIBRARIES=true
deploy:
  provider: surge
  skip_cleanup: true
  project: ./_site/
  domain: https://mysite.surge.sh
on:
  branch: master