Heroku-specific error

[fontiago]

Everything appears to be set up to the point of having the repo on Heroku, but when I run bundle exec ebooks start on Heroku (through Heroku CLI, heroku run bash), I get the following output:

~ $ bundle exec ebooks start
fatal: Not a git repository (or any parent up to mount point /app)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
@fontiagoebooks: User information updated
/app/lib/twitter_ebooks/model.rb:49:in `load': dump format error(0x2) (ArgumentError)
    from /app/lib/twitter_ebooks/model.rb:49:in `block in load'
    from /app/lib/twitter_ebooks/model.rb:48:in `instance_eval'
    from /app/lib/twitter_ebooks/model.rb:48:in `load'
    from bots.rb:22:in `on_startup'
    from /app/lib/twitter_ebooks/bot.rb:371:in `fire'
    from /app/lib/twitter_ebooks/bot.rb:353:in `prepare'
    from /app/bin/ebooks:361:in `block (2 levels) in start

And when I run simply ebooks start on Heroku:

~ $ ebooks start
/app/vendor/ruby-2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- twitter_ebooks (LoadError)
    from /app/vendor/ruby-2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /app/bin/ebooks:4:in `<main>'

Both of these commands work locally on my machine (OS X El Capitan). I'm guessing I've mucked something up with git, as evidenced by the fact that I can run bundle exec ebooks archive <username> corpus/<username>.json:

fatal: Not a git repository (or any parent up to mount point /app)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
Currently 3253 tweets for <username>
No new tweets

and that works the same as my local machine aside from the git repository error. Any help?

[fontiago]

Should be noted that it... obviously is a git repo, and when I run git init on Heroku it simply removes the git repository errors without fixing anything else.