Fix cache bug

src/models/fueltank.rs

@@ -1,3 +1,4 @@
+use std::env::temp_dir;
 use std::fmt::Debug;
 use std::fs;
 use std::path::PathBuf;
@@ -38,8 +39,7 @@ impl FuelTank {
               U: DeserializeOwned, U: Pump<T>
     {
         let path = PathBuf::new()
-            .join(home_dir().ok_or(ManifoldError::from("No home dir"))?)
-            .join(".local")
+            .join(temp_dir())
             .join(format!("manifold-{}-cache-{}.json", self.cache_name.clone().unwrap(), CACHE_VERSION));
 
         let mut fuel = match self.cache_mode {
@@ -50,6 +50,7 @@ impl FuelTank {
                     debug!("Cache path: {:?}", &path);
                     fs::OpenOptions::new()
                         .read(true)
+                        .write(true)
                         .create(true)
                         .open(&path)
                         .map_err(|e| {