all: update README

README.md

@@ -1,27 +1,76 @@
 # redir [![PkgGoDev](https://pkg.go.dev/badge/changkun.de/x/redir)](https://pkg.go.dev/changkun.de/x/redir) ![](https://changkun.de/urlstat?mode=github&repo=changkun/redir)
 
-The request redirector for changkun.de.
+Self-hosted link shortener and request redirector.
+
+## Features
+
+- Link shortner: support `/s` for short semantic alias and `/r` for anonymous shortening
+- Go's [Vanity Import](https://golang.org/cmd/go/#hdr-Remote_import_paths): redirect `domain/x` to configured VCS and `pkg.go.dev` for API documentation
+- PV/UV timeline visualization
+- Visitor referer visualization
+- Visitor device visualization
+- ...More
 
 ![](./demo.png)
 
+Index page at: [changkun.de/s](https://changkun.de/s).
+
 ## CLI Usage
 
 ```
-redir -a changkun -l https://changkun.de
-redir -l https://changkun.de
-redir -f import.yml
-redir -op fetch -a changkun
-redir -op update -a changkun https://blog.changkun.de
-redir -op delete -a changkun
+$ redir -a changkun -l https://changkun.de
+$ redir -l https://changkun.de
+$ redir -f import.yml
+$ redir -op fetch -a changkun
+$ redir -op update -a changkun -l https://blog.changkun.de
+$ redir -op delete -a changkun
+```
+
+## Deployment
+
+Build native binary:
+
+```sh
+$ make
+$ redir -s # run the server
+```
+
+Build and deploy with Docker:
+
+```
+$ docker network create traefik_proxy
+$ make build && make up
 ```
 
-## Troubleshooting
+## Configuration
+
+The [default configuration](./config.yml) is embedded into the binary.
+
+Alternative configuration can be used to replace default config and specified in environtment variable `REDIR_CONF`, for example `REDIR_CONF=/path/to/config.yml redir -s` to run the redir server under given configuration.
+
+## Troubleshooting regarding Private Vanity URL Imports
+
+
 
 ```
-git config --global url."[email protected]:".insteadOf "https://github.com/"
-echo "export GOPRIVATE=changkun.de/x" >> ~/.zshrc
+$ git config --global url."[email protected]:".insteadOf "https://github.com/"
+$ echo "export GOPRIVATE=changkun.de/x" >> ~/.zshrc
 ```
 
+## Who is using this service?
+
+Existing famous link shortener service, such as `bitly`, `tinyurl`, etc.,
+offers similar features but requires an unreasonably overpriced subscription fee.
+Therefore, the initial purpose of building this service is to support link
+shortener under domain [changkun.de](https://changkun.de), and
+it is the currently active user of this service.
+
+Project `redir` was initially written under [golang.design/s/redir](https://golang.design/s/redir),
+due to the different requirements, but this project has branched out from it
+and now has a different architecture and feature set.
+
+To know more users, check our [wiki](https://github.com/changkun/redir/wiki) page.
+
 ## License
 
 MIT © 2020-2021 [Changkun Ou](https://changkun.de)