Changes to cache location

Dockerfile

@@ -1,5 +1,7 @@
 FROM rust:1.76.0
 
+ENV CURRENCY_CACHE="/tmp/docker_currency_cache.db"
+
 WORKDIR /usr/src/currency-exchange
 
 COPY . .

src/config.rs

@@ -1,6 +1,6 @@
 use std::{
     env::{temp_dir, var_os},
-    path::PathBuf
+    path::PathBuf,
 };
 
 pub const CACHE_LOCATION_ENV_NAME: &str = "CURRENCY_CACHE";
@@ -18,12 +18,19 @@ pub fn get_endpoint() -> String {
 }
 pub fn get_cache_path() -> PathBuf {
     let mut path: PathBuf = PathBuf::new();
+
     match var_os(CACHE_LOCATION_ENV_NAME) {
         Some(val) => path.push(val),
+        None => match var_os("XDG_CACHE_HOME") {
+            Some(val) => {
+                path.push(val);
+                path.push("currencyCache.db");
+            }
             None => {
                 path.push(temp_dir());
                 path.push("currencyCache.db");
             }
+        },
     }
 
     path