Mention empty commits and skip CI

Author: martialblog

day1/04_Commits/02_Commits.md

@@ -20,6 +20,11 @@ Additionally, the date, time, and the checksum of the previous commit are stored
 user name and email address as commit author. This command opens the configured editor
 requiring you to add a commit message.
 
+You can also create empty commits. This is sometimes done with the initial commit in a repository:
+
+    @@@Sh
+    git commit --allow-empty -m "Initial commit"
+
 ~~~ENDSECTION~~~
 
 !SLIDE smbullets

day2/03_CI/04_Gitlab_Pipelines.md

@@ -81,6 +81,8 @@ Documentation: https://docs.gitlab.com/ce/ci/yaml/README.html#stage
 * Commit the changes
 * Check the GitLab Job Pipelines
 
+Hint: You can add `[ci skip]` or `[skip ci]` to your commit message.
+
 !SLIDE supplemental solutions
 # Lab ~~~SECTION:MAJOR~~~.~~~SECTION:MINOR~~~: Proposed Solution
 ****