skeleton of new worker architecture section

Worker.md

@@ -47,9 +47,18 @@ These information are sent to the broker on startup using the `init` command.
 
 ## Architecture
 
-Picture below is internal architecture of worker which shows its defined classes with private variables and public functions.
+### Internal communication
 
-[comment]: TODO: FIX THIS: ![Worker class diagram](https://rawgit.com/ReCodEx/wiki/master/images/worker_class_diagram.svg)
+- listener/evaluator and their responsibilities - who sends jobs, progress etc
+
+### File management
+
+- caching, downloading, cleaning
+
+### Running student submissions
+
+- killing isolate
+- sandboxing requirements
 
 ## Installation