add description

README.md

@@ -1,2 +1,26 @@
 # ytt.vim
-syntax for ytt
+
+vim plugin for [ytt](https://get-ytt.io)
+
+## Install
+To install using [Vim-Plug](https://github.com/junegunn/vim-plug):
+
+```
+" add this line to your .vimrc file
+Plug 'cappyzawa/starlark.vim'
+Plug 'cappyzawa/vault.nvim'
+```
+
+This plugin requires [cappyzawa/starlark\.vim: vim plugin for starlark](https://github.com/cappyzawa/starlark.vim).
+
+## Supported commands
+|Command|Description|
+|:---|:---|
+|EnableYtt|enable ytt syntax|
+|DisableYtt|disable ytt syntax|
+
+## Key mappings
+|Map|Key|Command|
+|:---:|:---:|:---|
+|nmap|<Leader\>ey|EnableYtt|
+|nmap|<Leader\>dy|DisableYtt|