Add client-side hook

utils/hooks/pre-commit

@@ -0,0 +1,31 @@
+#!/bin/sh
+
+checkout_branch="$(git branch --show-current)"
+presentations_indexed_files="$(git diff --cached --name-only -- presentations/ | wc -l)"
+indexed_files="$(git diff --cached --name-only | wc -l)"
+
+case "$checkout_branch" in
+    master)
+        if [ "${presentations_indexed_files}" -gt 0 ]
+        then
+            cat <<\EOF
+Error: Attempt to add files in presentations folder in master branch.
+Files in presentations folder are to be added in special branches xelatex/*.
+EOF
+            exit 1
+        fi
+        ;;
+    xelatex/*)
+        if [ $presentations_indexed_files -ne $indexed_files ]
+        then
+            cat <<\EOF
+Error: Attempt to add files outside presentations folder in special branch xelatex/*.
+This branch follows only files in presentations folder.
+EOF
+            exit 1
+        fi
+        ;;
+    *) exit 0;;
+esac
+        
+exit 0