add index, rename tutorial docs

customers-x/_index.zd

@@ -0,0 +1,5 @@
+:title "Index"
+:menu-order 98
+:desc /
+shows database structure in a compact format. folds documents which have >20 children.
+:zd/index

customers-x/timeline.zd

@@ -1,4 +1,5 @@
 :title "Timeline"
+:icon [:fa-duotone :fa-list-timeline]
 :menu-order 99
 :desc /
 shows history of changes in zendoc repo from git remote

customers-x/tutorial/doc/visuals.zd

@@ -0,0 +1,44 @@
+
+:title "3. Visual ways to think in data"
+
+:desc /
+
+zendoc includes support for [mermaid](https://mermaid.js.org/) and mindmaps.
+
+:mermaid mm/
+---
+title: Animal example
+---
+classDiagram
+ note "From Duck till Giraffe"
+ Animal <|-- Duck
+ note for Duck "can fly\ncan swim\ncan dive\ncan help in debugging"
+ Animal <|-- Fish
+ Animal <|-- Zebra
+ Animal : +int age
+ Animal : +String gender
+ Animal: +isMammal()
+ Animal: +mate()
+ class Duck{
+ +String beakColor
+ +swim()
+ +quack()
+ }
+ class Fish{
+ -int sizeInFeet
+ -canEat()
+ }
+ class Zebra{
+ +bool is_wild
+ +run()
+ }
+
+:mindmap mindmap/
+
+What is mindmap?
+ * It is a tool for thought
+ * ask questions
+ * structure knowledge
+ * It is a brainstorm method
+ * set goals
+ * generate ideas

customers-x/tutorial/1doc/zentext.zd → customers-x/tutorial/doc/zentext.zd

@@ -1,3 +1,4 @@
+
 :title "2. Zentext markup language"
 :desc /