[doc] update readme for simple description.

README.md

@@ -1,4 +1,62 @@
-# fzf-rs
-An experimental clone of fzf in rust
+FZF in Rust. [fzf](https://github.com/junegunn/fzf) is a command-line fuzzy finder written in Go while [fzf-rs](https://github.com/lotabout/fzf-rs) is a re-implementation in Rust!
 
-Requires nightly version
+TODO: add gif
+
+# Usage
+
+Current requires nightly rust to build. clone the repo and run:
+
+```
+cargo build --release
+```
+
+and put the resulting `target/release/fzf-rs` executable on your PATH.
+
+Now try out the following commands:
+
+```
+# directly input fzf-rs
+fzf-rs
+
+# or pipe some input to it: (press TAB key select multiple items with -m enabled)
+vim $(find . -name "*.rs" | fzf-rs -m)
+```
+The above command will allow you to select files with ".rs" extension and open
+the ones you selected in vim.
+
+## Key bindings
+
+Some common used keybindings.
+
+| key | Action |
+|---:|---|
+| Enter | Accept (select current one and quit)  |
+| ESC/Ctrl-G/Ctrl-Q | Abort|
+| Ctrl-P/Up | Move cursor up|
+| Ctrl-N/Down | Move cursor Down|
+| TAB | Toggle selection and move down (with `-m`)|
+| Shift-TAB | Toggle selection and move up (with `-m`)|
+
+Basically keys work in fzf will work in `fzf-rs`.
+
+# About fzf-rs
+
+One target of `fzf-rs` is to be compatible with `fzf`, so that we can re-use
+all the plugins(such as fzf.vim) that comes with `fzf`. Of course now it is
+far from finished.
+
+## Difference to fzf
+
+This project is written from scratch. Some decisions of impelmentation are
+different from fzf. For example:
+
+1. The fuzzy search algorithm is different.
+2. UI of showing matched items. `fzf` will show only the range matched while
+   `fzf-rs` will show each character matched.
+3. The implementation details are quite different if you care.
+
+## How to contribute
+
+Feel free to [create new
+issue](https://github.com/lotabout/fzf-rs/issues/new) if you meet any bugs
+or have any ideas.