My repo uses a customized version of Recurly-js, and I have packaged it as a submodule using these instructions https://devcenter.heroku.com/articles/git-submodules . However, I get the following error now when I try to deploy:
----> Heroku receiving push 
-----> Git submodules detected, installing
       Submodule 'recurly-js' (/app/tmp/repo.git/recurly-js) registered for path 'recurly-js'
       Initialized empty Git repository in /tmp/build_3iacvn8h2rnha/recurly-js/.git/
       fatal: '/app/tmp/repo.git/recurly-js' does not appear to be a git repository
       fatal: The remote end hung up unexpectedly
       Clone of '/app/tmp/repo.git/recurly-js' into submodule path 'recurly-js' failed
 !     Heroku push rejected, Submodule install failed
 
     
     
     
    