[Recipe] Use a global .gitignore file

If you want to use a global .gitignore file shared by all your Git projects, just follow the next steps.

Create the file, e.g. at your dotfiles directory:
```
$ touch ~/.dotfiles/gitignore
```

Fill it with whatever you want:

❯ cat ~/.dotfiles/gitignore
.DS_Store
.vscode/
*.log
node_modules/

Set Git’s option core.excludesfile to the path of the previous file:
```
$ git config --global core.excludesfile ~/.dotfiles/gitignore
```

Done.

You can change the ~/.dotfiles/gitignore path to wherever you have your global .gitignore file.

Error cause: email field should be unique. It is not asked at user creation time and because of that, it’s saved as blank on the database. There is a current user with an empty email in the database, thus, it throws the violation of the unique value constraint.