add README

Author: cappyzawa

README.md

@@ -1 +1,33 @@
-# vault.nvim
+# vault.nvim
+utilities to operate vault
+
+## Required
+* nvim 0.4.0++
+## Installation
+To install using [Vim-Plug](https://github.com/junegunn/vim-plug):
+```
+" add this line to your .vimrc file
+Plug 'cappyzawa/vault.nvim'
+```
+## Supported commands
+|Command|Description|
+|:---|:---|
+|VaultPathPrefix|set your secret path's prefix.|
+|VaultField|set your secret's field. default:`value`.|
+|VaultRead|`vault read -field <field> <path_prefix>/<selected string>`|
+
+## Key mappings
+If `g:vault_no_default_mappings` is not set to `v:true`, this plugin also defines following default mapping.
+
+|Map|Key|Command|
+|:---:|:---:|:---|
+|nmap|<Leader\>vpp|VaultPathPrefix|
+|nmap|<Leader\>vf|VaultField|
+|xmap|<Leader\>vr|VaultRead|
+|nmap|<Leader\>vr|VaultRead|
+
+`VaultRead` reads the secret of the selected string and displays it in the popup window.(xmap) 
+
+When popup is open, execute `VaultRead` to close it.(nmap)
+
+