Add method to check job extension on path

src/job.rs

@@ -63,6 +63,20 @@ impl Job {
         };
     }
 
+    pub fn has_job_file_extension(path: &Path) -> bool {
+        match path.extension() {
+            Some(x) => {
+                if ! "job".eq(x) {
+                    return false;
+                }
+            },
+            None => {
+                return false;
+            }
+        };
+        return true;
+    }
+
     pub fn new(url: &str, selector: &str, conf: &Conf) -> Job {
         let mut job = Job::default(conf);
         job.url = url.to_string();