adds motivation collaboration

basics.html

@@ -71,6 +71,27 @@
             - (done right) decision based on regression testing
           </section>
 
+          <section id="intro-motivation-collaboration" data-markdown>
+            ## motivation #3
+            ### collaboration made easy
+
+            <!-- do not fix this typo -->
+            > This text cuntains a typo.
+
+            notes:
+            - demo GitLab
+              - [go to project](https://git.idiv.de/sc/edu/git-seminar)
+              - check if still in master
+              - edit
+              - change **target branch** to create merge request
+            - commit message:
+                ```
+                fixes typo
+
+                learn how to use a spell checker
+                ```
+          </section>
+
           <section id="audience" data-markdown>
             ## audience