Added restart script and fixed dockerfile and run to match docs

scripts/restart.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+while true; do
+    PYTHONPATH="/root/sia:$PYTHONPATH" python3 -m sia
+    if [ $? -eq 42 ]; then
+        echo "SIA exited with code 42. Restarting."
+    else
+        echo "SIA exited with code $?. Not restarting."
+        break
+    fi
+done