Add section on gitlab, update reference.

book/_toc.yml

@@ -11,3 +11,4 @@ parts:
     - file: workflows/git-basic
       sections:
       - file: workflows/stage-commit-push
+    - file: workflows/gitlab

book/workflows/git-basic.md

@@ -6,10 +6,10 @@ In this section you will learn how to perform basic Git actions in VS Code. Cour
 Git is a version control system (VCS). In short, a VCS is a tool that helps you keep track of changes to you codebase (e.g., a Jupyter Book project!) over time. It allows you to keep track of the history of changes made to your code, work collaboratively with others, and revert to a previous version of the code if needed. 
 
 ## What is GitLab?
-GitLab is platform that hosts Git repositories, which can also be accessed through a web interface. Essentially, GitLab hosts the main repository that the members of a project interact with. Additionally, GitLab has plenty of other useful features such as issue tracking and code review. A selection of these features that are particularly useful for us as Jupyter Book developers will be highlighted in a [later section](gitlab).
+GitLab is platform that hosts Git repositories, which can also be accessed through a web interface. Essentially, GitLab hosts the main repository that the members of a project interact with. Additionally, GitLab has plenty of other useful features such as issue tracking and code review. A selection of these features that are particularly useful for us as Jupyter Book developers will be highlighted in a {ref}`later section <gitlab>.
 
 ## Terminology
-This is a (non-exhaustive) list of Git-related terminology that will be used throughout this section:
+This is a (non-exhaustive) list of terminology that will be used throughout this section:
 
 - Repository: a collection of files and folders, along with a history of their changes and who made them. 
 - Commit: a snapshot of the current state of the repository.

book/workflows/gitlab.md

@@ -0,0 +1,2 @@
+(gitlab)=
+# Useful GitLab features