Add missing documentation on how to add an alias in Github

### Overview
We need to add documentation, so that developers can add a git alias to the global git config

### Action Items
- [ ] Add content in the What's missing? section below to a new numbered item and linked page here: https://hackforla.github.io/peopledepot/contributing/howto/, editing or revising if necessary

### Resources/Instructions/Tags

- 1.01 git

### Documentation Addition Notes
#### What's missing?
This is the process for adding a git alias to the global git config:

1. Run this in the terminal:

```bash
git config --global -e
```

2. That will open an editor in which you can edit the global git config file.

3. Add the git alias under the `[alias]` section and save the file. The alias is now available for use.

#### Where should it go?
- https://hackforla.github.io/peopledepot/contributing/howto/

#### When would this information have been useful?
- Wherever documentation says to add a git alias

#### Which roles will benefit most from this information?
- Backend/ Dev