Merge branch 'add-git-training-march-21' into 'develop'

add slides for upcoming git training

See merge request !96

2021/2021-03-18_basicGitTraining/slides/what_is_git.md

+# What is `git`?
+
+<!-- ![](slides/img/git_definition.png) -->
+
+`git` is a **version control system** (VCS) for tracking changes in computer files and coordinating work on those files among multiple people [1].
+
+Designed and implemented in 2005 by **Linus Torvalds**
+
+<div align="center">
+<img src="slides/img/linus.jpg">
+</div>
+
+[1] *https://en.wikipedia.org/wiki/Git*
+
+
+
+# The inventor of `git`
+
+<div align="center">
+<img src="slides/img/git_definition.png">
+</div>
+
+`I'm an egotistical bastard, and I name all my projects after myself.
+First Linux, now git.`
+Linus Torvald (2007-06-14)
+
+
+
+# What is the use of `git`?
+
+* No need to fully rewrite code; **reuse code** and **save time**
+* Keep the changes you made over time (**history**)
+* Allows you to **backtrack** (if necessary) and undo unwanted changes
+* Easily **add contributions** of your collaborators to the main code base
+
+note:
+
+Other points to mention:
+* git shall not be considered as a nuisance, but as a tool that should help to track and trace the code.
+* git is not to track performance. Not using it shows exactly the opposite.