Create template for day 2 repetition/exercises

[theFeu]

I think it's pretty cool to start into day 2 with a few exercises to jog people's memory and wake 'em up. So, what we had so far was a modified version of this base template:

1. use `cd` to leave the training repository
1.1 make new local repository

2. add a new local name and email in gitconfig
2.1 verify local config

3. add a readme and commit
3.1 note commit id
3.2 make changes in readme and amend commit
3.3 compare commit ids

4. create a feature/testdata branch
4.1. switch to branch

5. make directory called 'testdata'
5.1 check status
5.2 add empty file called .keep in testdata
5.3 check status again
5.4 commit new directory

6. fill testdata with a file and commit

7. go to main branch and commit edits in readme

8. cherry-pick (with the -x flag) the first commit from feature/testdata
8.1 check git log

9. add .gitignore that ignores the testdata and commit
9.1. check tig

10. git merge (with the --no-ff flag) the feature/testdata branch
10.1. check tig again

We should totally go over it and collab on a new version though.