Update _toc.yml

Author: sukunis

docs/_toc.yml

@@ -7,6 +7,15 @@ parts:
   - caption: Specifications
     chapters:
     - file: specification/index
+  - caption: Tools
+    chapters:
+    - file: tools/index.md
+  - caption: Guidelines
+    chapters:
+    - file: guidelines/index.md
+  - caption: Use-Cases
+    chapters:
+    - file: use-cases/index.md
   - caption: Contributing
     chapters:
     - file: contributing/index