[hp-populate-remote] Implement hands on hp-populate-remote (#78)

## Exercise Discussion

This PR will close #56. Below is a more detailed description of the
changes along with implementation notes:

1. Added an `add_origin` function in `exercise_utils/git.py`. This might
be helpful in the future. I noticed that there is already a
`remove_remote` implementation, and `add_origin` is intended to be used
in a similar way.
2. To help ensure that the remote repository `gitmastery-things` is
created successfully across multiple attempts, I added a check to delete
any existing remote repository with the same name. Please note that this
requires setting up delete access for the GitHub CLI via `gh auth
refresh -h github.com -s delete_repo`. I also realised that the GitHub
CLI needs to be configured beforehand for this part of the hands-on to
work.

**Note:** The download script tested via `test-download.sh` works fine.
[Here](https://github.com/oadultradeepfield/gitmastery-things) is the
remote repo I managed to create.

## Checklist

- [ ] If you require a new remote repository on the `Git-Mastery`
organization, have you [created a
request](https://github.com/git-mastery/exercises/issues/new?template=request_exercise_repository.md)
for it?
- [ ] Have you written unit tests using
[`repo-smith`](https://github.com/git-mastery/repo-smith) to validate
the exercise grading scheme?
- [X] Have you tested the download script using `test-download.sh`?
- [X] Have you verified that this exercise does not already exist or is
not currently in review?
- [ ] Did you introduce a new grading mechanism that should belong to
[`git-autograder`](https://github.com/git-mastery/git-autograder)?
- [ ] Did you introduce a new dependency that should belong to
[`app`](https://github.com/git-mastery/app)?

Author: oadultradeepfield

hands_on/populate_remote.py

@@ -0,0 +1,67 @@
+import os
+
+from exercise_utils.file import append_to_file, create_or_update_file
+from exercise_utils.git import add, add_remote, commit, init
+from exercise_utils.github_cli import (
+    create_repo,
+    delete_repo,
+    get_github_username,
+    has_repo,
+)
+
+__requires_git__ = True
+__requires_github__ = True
+
+REPO_NAME = "gitmastery-things"
+
+
+def download(verbose: bool):
+    _setup_local_repository(verbose)
+    _create_things_repository(verbose)
+    _link_repositories(verbose)
+
+
+def _setup_local_repository(verbose: bool):
+    os.makedirs("things")
+    os.chdir("things")
+    init(verbose)
+
+    create_or_update_file(
+        "fruits.txt",
+        """
+        apples
+        bananas
+        cherries
+        dragon fruits
+        """,
+    )
+    add(["fruits.txt"], verbose)
+
+    append_to_file("fruits.txt", "figs")
+    add(["fruits.txt"], verbose)
+    commit("Insert figs into fruits.txt", verbose)
+
+    create_or_update_file("colours.txt", "a file for colours")
+    create_or_update_file("shapes.txt", "a file for shapes")
+    add(["colours.txt", "shapes.txt"], verbose)
+    commit("Add colours.txt, shapes.txt", verbose)
+
+
+def _create_things_repository(verbose: bool):
+    """Create the gitmastery-things repository, deleting any existing ones."""
+    full_repo_name = _get_full_repo_name(verbose)
+
+    if has_repo(full_repo_name, False, verbose):
+        delete_repo(full_repo_name, verbose)
+
+    create_repo(REPO_NAME, verbose)
+
+
+def _link_repositories(verbose: bool):
+    full_repo_name = _get_full_repo_name(verbose)
+    add_remote("origin", f"https://github.com/{full_repo_name}", verbose)
+
+
+def _get_full_repo_name(verbose: bool) -> str:
+    username = get_github_username(verbose)
+    return f"{username}/{REPO_NAME}"