Update contribute

docs/development.md

@@ -9,3 +9,22 @@
 If you get any issues, please open an issue with the ISSUE_TEMPLATE. It is useful for me to debug for this issue.
 
 ## Contribute Layers
+
+1. fork SpaceVim repo
+2. add a layer file `autoload/SpaceVim/layers/foo.vim` for `foo` layer.
+3. edit layer file, check out the example below:
+
+```vim
+function! SpaceVim#layers#foo#plugins() abort
+    let plugins = []
+    call add(plugins, ['Shougo/foo.vim', {'option' : 'value'}])
+    return plugins
+endfunction
+
+
+function! SpaceVim#layers#foo#config() abort
+    " here you can set some value or mappings
+endfunction
+```
+
+4. send PR to SpaceVim.

docs/documentation.md

@@ -10,7 +10,7 @@
     - [Unite centric work-flow](#unite-centric-work-flow)
     - [multiple leader mode](#multiple-leader-mode)
 - [Custom configuration](#custom-configuration)
-- [Layers](#layers)
+- [Layers](https://spacevim.org/layers)
 
 # Features