Allow token to be specified via env var

Author: FiveYellowMice

README.en.md

@@ -63,7 +63,7 @@ OPTIONS:
         --min-interval <seconds>    Minimum fetch interval [default: 300]
 
 ARGS:
-    <token>    Telegram bot token
+    <token>    Telegram bot token [env: RSSBOT_TOKEN]
 
 NOTE: You can get <user id> using bots like @userinfobot @getidsbot
 ```
@@ -72,6 +72,7 @@ Please read the [official docs](https://core.telegram.org/bots#3-how-do-i-create
 
 ## Environment variables
 
+- `RSSBOT_TOKEN`: Telegram bot token
 - `HTTP_PROXY`: Proxy for HTTP
 - `HTTPS_PROXY`: Proxy for HTTPS
 - `RSSBOT_DONT_PROXY_FEEDS`: Set to `1` to limit the proxy to Telegram requests

README.md

@@ -61,7 +61,7 @@ OPTIONS:
         --min-interval <seconds>    Minimum fetch interval [default: 300]
 
 ARGS:
-    <token>    Telegram bot token
+    <token>    Telegram bot token [env: RSSBOT_TOKEN]
 
 NOTE: You can get <user id> using bots like @userinfobot @getidsbot
 ```
@@ -70,6 +70,7 @@ NOTE: You can get <user id> using bots like @userinfobot @getidsbot
 
 ## 环境变量
 
+- `RSSBOT_TOKEN`: Telegram bot token
 - `HTTP_PROXY`: 用于 HTTP 的代理
 - `HTTPS_PROXY`: 用于 HTTPS 的代理
 - `RSSBOT_DONT_PROXY_FEEDS`: 设为 `1` 使所有订阅的 RSS 不通过代理（仅代理 Telegram）

src/main.rs

@@ -39,6 +39,10 @@ static BOT_ID: OnceLock<tbot::types::user::Id> = OnceLock::new();
 )]
 pub struct Opt {
     /// Telegram bot token
+    #[structopt(
+        env = "RSSBOT_TOKEN",
+        hide_env_values = true
+    )]
     token: String,
     /// Path to database
     #[structopt(