Sometimes a Gemfile references other files. Such as `.ruby-version` or vendored gems. When copying the Gemfile to the nix store we need to copy those files alongside. This can be done using `extraConfigPaths`. For example:
```nix
gems=bundlerEnv{
name="gems-for-some-project";
gemdir=./.;
extraConfigPaths=["${./.}/.ruby-version"];
};
```
### Gem-specific configurations and workarounds {#gem-specific-configurations-and-workarounds}
In some cases, especially if the gem has native extensions, you might need to modify the way the gem is built.
