tasks.get returns null on not found

src/taskworker.js

@@ -72,8 +72,8 @@ async.series([
     debug(`Starting task ${taskId}. Logs are at ${logFile}`);
 
     const [getError, task] = await safe(tasks.get(taskId));
-    if (getError) {
-        debug(getError);
+    if (getError || !task) {
+        debug(getError ? `Error getting task: ${getError.message}` : 'Task not found');
         return process.exit(50);
     }