Update readme

README.md

@@ -2,3 +2,25 @@
 
 What do you do when you wanna mess with a new programming language? You make a
 URL shortener, duh!
+
+## Usage
+
+### via CLI
+
+```
+$ ozuio --help
+usage: ozuio [<flags>]
+
+Flags:
+      --help                  Show context-sensitive help (also try --help-long and --help-man).
+  -p, --port="8080"           Port to listen to.
+  -b, --bind="0.0.0.0"        Bind address.
+  -d, --dir="ozuio_database"  Directory to store database file.
+  -v, --version               Print version info.
+```
+
+### via Docker
+
+```
+$ docker run -d --name ozu.io -p 8080:8080 -v /ozuio_data:/data jimeh/ozu.io
+```