作成したRailsアプリを

$ git push heroku master

すると、以下のエラーが発生します。

remote: -----> Ruby app detected
remote: -----> Compiling Ruby/Rails
remote: -----> Using Ruby version: ruby-2.3.4
remote: -----> Installing dependencies using bundler 1.13.7
remote:        Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin -j4 --deployment
remote:        Warning: the running version of Bundler (1.13.7) is older than the version that created the lockfile (1.14.3). We suggest you upgrade to the latest version of Bundler by running `gem install bundler`.
remote:        Fetching gem metadata from https://rubygems.org/..........
remote:        Fetching version metadata from https://rubygems.org/..
remote:        Fetching dependency metadata from https://rubygems.org/.
remote:        Installing i18n 0.8.0
remote:        Installing rake 12.0.0
remote:        Installing concurrent-ruby 1.0.4
remote:        Installing minitest 5.10.1
remote:        Installing thread_safe 0.3.5
remote:        Installing builder 3.2.3
remote:        Installing erubis 2.7.0
remote:        Installing mini_portile2 2.1.0
remote:        Installing rack 2.0.1
remote:        Installing nio4r 1.2.1 with native extensions
remote:        Installing websocket-extensions 0.1.2
remote:        Installing mime-types-data 3.2016.0521
remote:        Installing arel 7.1.4
remote:        Installing execjs 2.7.0
remote:        Installing bcrypt 3.1.11 with native extensions
remote:        Installing sass 3.4.23
remote:        Installing coffee-script-source 1.12.2
remote:        Installing method_source 0.8.2
remote:        Installing thor 0.19.4
remote:        Installing orm_adapter 0.5.0
remote:        Installing tilt 2.0.6
remote:        Installing multi_json 1.12.1
remote:        Installing nested_form 0.3.2
remote:        Installing puma 3.7.0 with native extensions
remote:        Using bundler 1.13.7
remote:        Installing remotipart 1.3.1
remote:        Installing ref 2.0.0
remote:        Installing simple-rss 1.3.1
remote:        Installing sqlite3 1.3.13 with native extensions
remote:        Your Gemfile.lock is corrupt. The following gem is missing from the DEPENDENCIES
remote:        section: 'libv8'
remote:        Bundler Output: Warning: the running version of Bundler (1.13.7) is older than the version that created the lockfile (1.14.3). We suggest you upgrade to the latest version of Bundler by running `gem install bundler`.
remote:        Fetching gem metadata from https://rubygems.org/..........
remote:        Fetching version metadata from https://rubygems.org/..
remote:        Fetching dependency metadata from https://rubygems.org/.
remote:        Installing i18n 0.8.0
remote:        Installing rake 12.0.0
remote:        Installing concurrent-ruby 1.0.4
remote:        Installing minitest 5.10.1
remote:        Installing thread_safe 0.3.5
remote:        Installing builder 3.2.3
remote:        Installing erubis 2.7.0
remote:        Installing mini_portile2 2.1.0
remote:        Installing rack 2.0.1
remote:        Installing nio4r 1.2.1 with native extensions
remote:        Installing websocket-extensions 0.1.2
remote:        Installing mime-types-data 3.2016.0521
remote:        Installing arel 7.1.4
remote:        Installing execjs 2.7.0
remote:        Installing bcrypt 3.1.11 with native extensions
remote:        Installing sass 3.4.23
remote:        Installing coffee-script-source 1.12.2
remote:        Installing method_source 0.8.2
remote:        Installing thor 0.19.4
remote:        Installing orm_adapter 0.5.0
remote:        Installing tilt 2.0.6
remote:        Installing multi_json 1.12.1
remote:        Installing nested_form 0.3.2
remote:        Installing puma 3.7.0 with native extensions
remote:        Using bundler 1.13.7
remote:        Installing remotipart 1.3.1
remote:        Installing ref 2.0.0
remote:        Installing simple-rss 1.3.1
remote:        Installing sqlite3 1.3.13 with native extensions
remote:        Your Gemfile.lock is corrupt. The following gem is missing from the DEPENDENCIES
remote:        section: 'libv8'
remote:  !
remote:  !     Failed to install gems via Bundler.
remote:  !
remote:  !     Push rejected, failed to compile Ruby app.
remote: 
remote:  !     Push failed
remote: Verifying deploy...

どうすればデプロイに成功するのかアドバイス頂きたく、よろしくお願いいたします。

開発環境
macOS
Ruby 2.4
Rails 5.0.1

追記
自己解決できました。
ブランチを切って作業していたのが原因でした。
変更をマスターブランチにマージしたらデプロイ出来ました。