diff --git a/hybrid-linux/index.js b/hybrid-linux/index.js
index 23cb8ea..ca88b53 100644
--- a/hybrid-linux/index.js
+++ b/hybrid-linux/index.js
@@ -1,6 +1,6 @@
 [
     {
-          "chapter": "1",
+          "chapter": 1,
           "title": "Start a Lab",
           "subtitle": "Absolute basics",
           "type": "video",
@@ -9,7 +9,7 @@
           "file": "510376917"
     },
     {
-          "chapter": "2",
+          "chapter": 2,
           "title": "An Introduction to Linux !",
           "subtitle": "Absolute basics",
           "type": "asciidoc",
@@ -17,7 +17,7 @@
           "file": "basics.adoc"
     },
     {
-          "chapter": "2",
+          "chapter": 2,
           "title": "An Introduction to Linux !",
           "subtitle": "Absolute basics",
           "type": "asciinema",
@@ -26,7 +26,7 @@
     },
 
     {
-          "chapter": "3",
+          "chapter": 3,
           "title": "Linux file system layout",
           "subtitle": "Absolute basics",
           "type": "asciidoc",
@@ -34,7 +34,7 @@
           "file": "filesystem.adoc"
     },
     {
-          "chapter": "3",
+          "chapter": 3,
           "title": "Linux file system layout",
           "subtitle": "Absolute basics",
           "type": "asciinema",
@@ -43,7 +43,7 @@
     },
 
     {
-          "chapter": "4",
+          "chapter": 4,
           "title": "The /proc Filesystem",
           "subtitle": "Absolute basics",
           "type": "asciidoc",
@@ -51,7 +51,7 @@
           "file": "proc.adoc"
     },
     {
-          "chapter": "4",
+          "chapter": 4,
           "title": "The /proc Filesystem",
           "subtitle": "Absolute basics",
           "type": "video",
@@ -60,7 +60,7 @@
           "file": "510376917"
     },
     {
-          "chapter": "4",
+          "chapter": 4,
           "title": "The /proc Filesystem",
           "subtitle": "Absolute basics",
           "type": "asciinema",
@@ -69,7 +69,7 @@
     },
 
     {
-          "chapter": "5",
+          "chapter": 5,
           "title": "Find and grep",
           "subtitle": "Absolute basics",
           "type": "asciidoc",
@@ -77,7 +77,7 @@
           "file": "find_and_grep.adoc"
     },
     {
-          "chapter": "6",
+          "chapter": 6,
           "title": "Managing software",
           "subtitle": "Absolute basics",
           "type": "asciidoc",
@@ -86,7 +86,7 @@
     },
 
     {
-          "chapter": "7",
+          "chapter": 7,
           "title": "Exercise",
           "subtitle": "subtitle",
           "type": "exercise",
@@ -95,7 +95,7 @@
           "file": "ex_find_and_grep.adoc"
     },
     {
-          "chapter": "7",
+          "chapter": 7,
           "title": "Exercise",
           "subtitle": "subtitle",
           "type": "exercise",
@@ -104,7 +104,7 @@
           "file": "ex_find_and_grep.adoc"
     },
     {
-          "chapter": "8",
+          "chapter": 8,
           "title": "Exercise",
           "subtitle": "subtitle",
           "type": "exercise",
@@ -113,7 +113,7 @@
           "file": "ex_find_and_grep.adoc"
     },
     {
-          "chapter": "9",
+          "chapter": 9,
           "title": "Exercise",
           "subtitle": "subtitle",
           "type": "exercise",
@@ -122,7 +122,7 @@
           "file": "ex_find_and_grep.adoc"
     },
     {
-          "chapter": "10",
+          "chapter": 10,
           "title": "Exercise",
           "subtitle": "subtitle",
           "type": "exercise",