Add previously ignore files to git
Lets assume we had a project that was ignoring the /proj/mymodule directory.
To add it to git for tracking. We need to make sure it is not a submodule. A submodule is another git project that is within our main project. If that is the case we need to delete the .git/ folder in /proj/mymodule.
Next we need to stop ignoring the file, ex, by removing it from our .gitignore file.
Clear the git index. (may not really be needed)
git rm --cached /myproj/mymodule
Forced add it to the respository
git add -f /myproj/mymodule