Modify the structure of README.md

Instead of having exercises in their own separate section,
they are now part of the main topics sections.

This should make the learning process easier to follow
where users have both exercises and questions in the same
place.

In addition, added a couple of new questions & exercises
and modified existing scripts accordingly.

exercises/git/branch_01.md

@@ -0,0 +1,19 @@
+## Git Commit 01
+
+### Objective
+
+Learn how to work with Git Branches
+
+### Instructions
+
+1. Pick up a Git repository (or create a new one) with at least one commit
+2. Create a new branch called "dev"
+3. Modify one of the files in the repository
+4. Create a new commit
+5. Verify the commit you created is only in "dev" branch
+
+### After you complete the exercise
+
+Answer the following:
+
+1. Why branches are useful? Give an example of one real-world scenario for using branches

exercises/git/commit_01.md

@@ -0,0 +1,20 @@
+## Git Commit 01
+
+### Objective
+
+Learn how to commit changes in Git repositories
+
+### Instructions
+
+1. Create a new directory
+2. Make it a git repository
+3. Create a new file called `file` with the content "hello commit"
+4. Commit your new file
+5. Run a git command to verify your commit was recorded
+
+### After you complete the exercise
+
+Answer the following:
+
+* What are the benefits of commits?
+* Is there another way to verify a commit was created?

exercises/git/solutions/branch_01_solution.md

@@ -0,0 +1,20 @@
+## Branch 01 - Solution
+
+```
+cd some_repository
+echo "master branch" > file1
+git add file1
+git commit -a -m "added file1"
+git checkout -b dev
+echo "dev branch" > file2
+git add file2
+git commit -a -m "added file2"
+```
+
+Verify:
+
+```
+git log (you should see two commits)
+git checkout master
+git log (you should see one commit)
+```

exercises/git/solutions/commit_01_solution.md

@@ -0,0 +1,10 @@
+## Git Commit 01 - Solution
+
+```
+mkdir my_repo && cd my_repo
+git init
+echo "hello_commit" > file
+git add file
+git commit -a -m "It's my first commit. Exciting!"
+git log
+```