read config from file whee

src/config.rs

@@ -1,6 +1,7 @@
 use serde::Serialize;
 use serde::Deserialize;
 use std::fs;
+use std::env;
 
 #[derive(Serialize, Deserialize, Debug)]
 pub struct Config {
@@ -24,7 +25,11 @@ struct Engine {
 }
 
 pub fn build_config() -> Config {
-   return build_config_std()
+   let config_path = env::var("CONFIG_PATH");
+   match config_path {
+      Ok(p) => return build_config_yaml(p),
+      Err(_) => return build_config_std(),
+   }
 }
 
 fn build_config_yaml(path: String) -> Config {