diff --git a/.gitignore b/.gitignore
index 79b5594..9007db7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 **/.DS_Store
+Knowledge.textbundle
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diff --git a/.nojekyll b/.nojekyll
new file mode 100644
index 0000000..e69de29
diff --git a/README.md b/README.md
index a82cc9c..d01aff1 100644
--- a/README.md
+++ b/README.md
@@ -6,4 +6,3 @@ The File format is in [MindNode](https://mindnode.com/)
 
 ## Preview
 
-![my knowledge mind mapping image](./Knowledge.png)
diff --git a/_coverpage.md b/_coverpage.md
new file mode 100644
index 0000000..064aa5f
--- /dev/null
+++ b/_coverpage.md
@@ -0,0 +1,12 @@
+<!-- _coverpage.md -->
+
+![logo](./cover.png)
+
+# The IT things I learned
+
+> Never stop learning and digesting.
+
+
+
+[GitHub](https://github.com/wahyd4/knowledge-mind-mapping)
+[Get Started](#knowledge-mind-mapping)
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diff --git a/_sidebar.md b/_sidebar.md
new file mode 100644
index 0000000..aef38f6
--- /dev/null
+++ b/_sidebar.md
@@ -0,0 +1,16 @@
+<!-- docs/_sidebar.md -->
+
+- [Home](/)
+- [**Go**](categories/go.md)
+- [Java](golang.md)
+- [JavaScript](golang.md)
+- [Ruby](golang.md)
+- [Interview](golang.md)
+- [Software Design](golang.md)
+- [Message Queue](golang.md)
+- [Database](golang.md)
+- [Application](golang.md)
+- [Web Scraping](golang.md)
+- [Devops](golang.md)
+- [Web](golang.md)
+- [Success Team Work](golang.md)
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diff --git a/categories/go.md b/categories/go.md
new file mode 100644
index 0000000..6614a36
--- /dev/null
+++ b/categories/go.md
@@ -0,0 +1,160 @@
+## Language
+
+### pass pointer or value
+- value: Variable must not be modified
+- Variable is a large struct  then prefer pointer
+- Variable is a map or slice then prefer value
+- Passing by value often is cheaper
+
+### struct
+
+- make
+    - make(T, args) -> T
+- new
+    - new(T) -> *T
+- a := T{}
+
+### Slice
+
+- Auto scale length
+    - new([]int)
+    - make([]int, 2, 5)
+
+### Go routine
+
+- you can run more goroutine vs thread
+- go routine have a fater startup time than thread
+- go routine come with built-in primitives to communicate safely by using channels
+
+### Closure
+
+### Channel
+
+- messages := make(chan string)
+        // _Send_ a value into a channel using the `channel <-`
+        go func() { messages <- "ping" }()
+        // channel. Here we'll receive the `"ping"` message
+        msg := <-messages
+
+- buffered channel
+
+    - ch := make(chan Task, 3)
+
+### Sync
+
+- atomic
+- Mutex
+    - sync.Mutex()
+    - mutex.Lock()
+    - mutx.Unlock()
+- string literals
+	- \`aaa bbb ccc\`
+- panic / recover
+
+## Frameworks
+
+### db
+
+- xorm
+- gorm
+
+### web
+
+- beego
+- mux
+- gin
+- go kit
+    - full stack micro service framework like spring boot
+
+### tools
+
+- profiler
+    - go-wrk(wrk)
+        - a http benchmark tool
+    - go-torch
+        - Stochastic flame graph profiler
+- test
+    - github.com/stretchr/testify
+
+## Tips
+
+### slice
+
+- byte* array //actual data
+- uintgo len
+- uintgo cap
+
+### map
+
+- implement by hash table
+
+### Go has no generics
+
+- performance
+- complexity
+- If C++ and Java are about type hierarchies and the taxonomy of types, Go is about composition.
+- How to solve
+    - use interface
+    - use type assertions
+    - use reflection
+
+### Modify item in range
+
+- use the array index instead of the value
+```go
+    for _, e := range array {
+        e.field = "foo"
+    }
+
+    for idx, _ := range array {
+        array[idx].field = "foo"
+    }
+```
+### merge two array
+
+- a = append(a, b…)
+    - must add … to b, otherwise you can only add one item
+
+### error handling
+
+- error type assertion
+    - if serr, ok := err.(*json.SyntaxError); ok {}
+
+- better error handling
+
+    - custom error type
+        - type appError struct {
+                Error   error
+                Message string
+                Code    int
+            }
+
+    - concat error check
+        - if err1() != nil || err2() != nil {}
+    - some error constants
+        - errNotFound = errors.New("Item not found")
+            switch err {
+                    case errNotFound:
+            }
+
+### date format
+
+- t := time.Now()
+    fmt.Println(t.String())
+    fmt.Println(t.Format("2006-01-02 15:04:05"))
+
+- var _ InterfaceX = &InterfaceXImplementation{}
+	- make sure InterfaceX’s implementation works
+
+## commands
+
+### test
+
+- go test ./...
+    -  run all tests in current directory and all of its subdirectories
+- go test foo/...
+    -  run all tests with import path prefixed with foo/:
+- go test foo...
+    - run all tests import path prefixed with foo:
+- go test ...
+    - run all tests in your $GOPATH:
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diff --git a/index.html b/index.html
new file mode 100644
index 0000000..a6c38ea
--- /dev/null
+++ b/index.html
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+    <meta charset="UTF-8">
+    <title>Document</title>
+    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />
+    <meta name="description" content="Description">
+    <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
+    <link rel="stylesheet" href="//unpkg.com/docsify/lib/themes/vue.css">
+</head>
+
+<body>
+    <div id="app">Please wait...</div>
+    <script>
+        window.$docsify = {
+            name: 'The IT things I learned',
+            repo: 'https://github.com/wahyd4/knowledge-mind-mapping',
+            loadSidebar: true,
+            subMaxLevel: 5,
+            formatUpdated: '{MM}/{DD} {HH}:{mm}',
+            coverpage: true
+        }
+    </script>
+    <script src="//unpkg.com/docsify/lib/docsify.min.js"></script>
+</body>
+
+</html>
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