12 recap so far

Let's recap what we know so far

1. We know of three types of objects in git:

- Blob
- Tree
- Commit

2. Objects are indexed by a sha1 hash based off
   of their content

3. Commits point to a tree i.e. a commit is a
   snapshot of all your files in a moment of time

4. Trees point to sub-trees or blobs, i.e. trees model
   directories

5. Blobs are used to save file contents

6. Commits also have parent(s), i.e. a pointer to
   the previous state of your files

Bonus Question:

Are there any other objects we have not considered?