fixed file uploads directory to be unique

app/controllers/v1/learning_objects/chunks_controller.rb

@@ -14,6 +14,9 @@ class V1::LearningObjects::ChunksController < ApplicationController
     if last_chunk?
       combine_file!
       post_file!
+
+      # TODO render new attachment ID
+      render  status: 200
     end
 
     render status: 200
@@ -108,7 +111,7 @@ class V1::LearningObjects::ChunksController < ApplicationController
   ##
   # /tmp/file-chunks
   def final_file_directory
-    File.join('tmp', 'file-chunks')
+    File.join('tmp', 'files', chunks_params[:_chunkIdentifier])
   end
 
   ##