Implement hands on hp-add-remote (#79)

# Exercise Review

## Exercise Discussion

#55 

## 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: woojiahao

hands_on/add_remote.py

@@ -0,0 +1,37 @@
+import os
+
+from exercise_utils.git import add, init, commit
+from exercise_utils.file import create_or_update_file, append_to_file
+
+__requires_git__ = True
+__requires_github__ = False
+
+
+def download(verbose: bool):
+    os.makedirs("things")
+    os.chdir("things")
+    init(verbose)
+    create_or_update_file(
+        "fruits.txt",
+        """
+        apples
+        bananas
+        cherries
+        dragon fruits
+        figs
+        """,
+    )
+    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)