Submission UUID generation moved to function

See issue #139

src/utils/getSubmissionUUID.js

@@ -0,0 +1,7 @@
+const getHash = require('./getHash.js');
+
+module.exports = function getSubmissionUUID(videoID, category, userID,
+  startTime, endTime) {
+  return getHash('v2-categories' + videoID + startTime + endTime + category +
+    userID, 1);
+};