[ci skip] Allow config file to set default values for flags

tools/asynqmon/README.md

@@ -2,6 +2,20 @@
 
 Asynqmon is a CLI tool to monitor the queues managed by `asynq` package.
 
+## Table of Contents
+
+- [Installation](#installation)
+- [Quick Start](#quick-start)
+  - [Stats](#stats)
+  - [History](#history)
+  - [List](#list)
+  - [Enqueue](#enqueue)
+  - [Delete](#delete)
+  - [Kill](#kill)
+- [Config File](#config-file)
+
+## Installation
+
 In order to use the tool, compile it using the following command:
 
     go get github.com/hibiken/asynq/tools/asynqmon
@@ -29,3 +43,41 @@ Example:
 This will run `asynqmon stats` command every 3 seconds.
 
 ![Gif](/docs/assets/asynqmon_stats.gif)
+
+### History
+
+TODO: Add discription
+
+### List
+
+TODO: Add discription
+
+### Enqueue
+
+TODO: Add discription
+
+### Delete
+
+TODO: Add discription
+
+### Kill
+
+TODO: Add discription
+
+## Config File
+
+You can use a config file to set default values for flags.
+This is useful, for example when you have to connect to a remote redis server.
+
+By default, `asynqmon` will try to read config file located in
+`$HOME/.asynqmon.(yml|json)`. You can specify the file location via `--config` flag.
+
+Config file example:
+
+```yml
+uri: 127.0.0.1:6379
+db: 2
+password: mypassword
+```
+
+This will set the default values for `--uri`, `--db`, and `--password` flags.