index.ipynb: Add 09_git.ipynb to the table of contents

Also add it (manually) to the README.md file.

Author: jnareb

README.md

@@ -60,6 +60,7 @@ Only the first command performs straight reachability query.
 6. [Topological levels](06_levels.ipynb)
 7. [DFS intervals labelling](07_interval_labels.ipynb)
 8. [Reachability queries](08_reach.ipynb)
+9. [Extracting commit graphs from Git repositories](09_git.ipynb)
 
 ## Slides
 

index.ipynb

@@ -107,7 +107,8 @@
     "5. [Reachability index](05_reachability_index.ipynb)\n",
     "6. [Topological levels](06_levels.ipynb)\n",
     "7. [DFS intervals labelling](07_interval_labels.ipynb)\n",
-    "8. [Reachability queries](08_reach.ipynb)"
+    "8. [Reachability queries](08_reach.ipynb)\n",
+    "9. [Extracting commit graphs from Git repositories](09_git.ipynb)"
    ]
   },
   {