update readme

README.md

@@ -1,3 +1,25 @@
 # icerbox.sh
+icerbox.com download cli in bash
 
-icerbox.com bash dl cli
+### features
+- premium downloads
+- skip existing files
+- parallel downloads with curl
+- honour daily download quota
+
+### todo
+- guest downloads
+
+### not supported
+- login captcha
+
+### account config
+
+`~/.icerbox.conf`
+```
+email='lain@example.church'
+password='present day'
+```
+### login rate limit
+
+if login fails with HTTP 429, use a browser to login and store the `Authorization Bearer` request header in `~/.icerbox.token`