Add description to Commands.md for git-ignore-io

Commands.md

@@ -20,6 +20,7 @@
  - [`git graft`](#git-graft)
  - [`git alias`](#git-alias)
  - [`git ignore`](#git-ignore)
+ - [`git ignore-io`](#git-ignore-io)
  - [`git info`](#git-info)
  - [`git fork`](#git-fork)
  - [`git release`](#git-release)
@@ -408,6 +409,54 @@ build
 *.log
 ```
 
+## git ignore-io
+
+Generate sample gitignore file from [gitignore.io](https://www.gitignore.io)  
+
+Without option, `git ignore` show the sample gitignore on screen.  
+
+```bash
+$ git ignore-io vim
+
+    # Created by https://www.gitignore.io/api/vim
+
+    ### Vim ###
+    [._]*.s[a-w][a-z]
+    [._]s[a-w][a-z]
+    *.un~
+    Session.vim
+    .netrwhist
+    *~
+```
+  
+To export it to `.gitignore` file you can use the following options:  
+
+* `-a` or `--append` to append the result to `.gitignore`
+* `-e` or `--export` to replace `.gitignore` with the result
+
+```bash
+$ git ignore-io vim python
+```
+
+For efficiency, `git ignore-io` store all available typess at `~/.gi_list`.  
+To list all the available types:
+
+* `-l` or `-L` : These two options will show the list in different format. Just try it.
+  
+You can also search type from the list by:
+
+* `-s <word>` or `--search <word>`
+
+```bash
+$ git ignore-io -s ja
+
+    django
+    jabref
+    java
+    ninja
+```
+
+
 ## git info
 
 Show information about the repo: