renamed execute_websocket_command to open_websocket_connection, because we now run the command after all listeners in the submissions controller were attached

app/controllers/submissions_controller.rb

@@ -111,6 +111,7 @@ class SubmissionsController < ApplicationController
 
       if result[:status] == :container_running
         socket = result[:socket]
+        command = result[:command]
 
         socket.on :message do |event|
           Rails.logger.info( Time.now.getutc.to_s + ": Docker sending: " + event.data)
@@ -139,6 +140,11 @@ class SubmissionsController < ApplicationController
             Rails.logger.debug('Rescued parsing error, sent the received client data to docker:' + data)
           end
         end
+
+        # Send command after all listeners are attached.
+        # Newline required to flush
+        socket.send command + "\n"
+        Rails.logger.info('Sent command: ' + command.to_s)
       else
         kill_socket(tubesock)
       end