git push heroku master will not recognize my Gemfile.lock file

问题

My first time pushing to Heroku using Git and I'm getting the error message: Gemfile.lock is required. Please run "bundle install" locally and commit your Gemfile.lock.

I have ran bundle install, added the files to the git repo, commited the changes. See the Gemfile.lock in both the repository and my directory but when I run the command git push heroku master it consistently throws that error.

What am I doing wrong:

Here is the git repo on my PC

$git ls-files
.bundle/config
.gitignore
.rspec
Gemfile
Gemfile.lock
README
Rakefile
app/assets/images/rails.png
app/assets/javascripts/application.js
app/assets/stylesheets/application.css
..<snip>..

Here is the git status of the repo.

$git status
# On branch ch_ruby_intro
# Your branch is ahead of 'origin/ch_ruby_intro' by 6 commits.
#
nothing to commit (working directory clean)

Error when I try to deploy.

$git push heroku master
Counting objects: 239, done.
Compressing objects: 100% (140/140), done.
Writing objects: 100% (239/239), 50.30 KiB, done.
Total 239 (delta 74), reused 215 (delta 67)

-----> Heroku receiving push
-----> Ruby/Rails app detected
 !
 !     Gemfile.lock is required. Please run "bundle install" locally
 !     and commit your Gemfile.lock.
 !
 !     Heroku push rejected, failed to compile Ruby/rails app

Why is it not seeing the Gemfile.lock file?