Updated .gitignore to ignore python virtual environment directory
Updated .gitignore to ignore python virtual environment directory

cuautograde/cuautograde,dhruvsinghal/autograding-tools,cuautograde/cuautograde,cuautograde/cuautograde,dhruvsinghal/autograding-tools,dhruvsinghal/autograding-tools,dhruvsinghal/cuautograde,dhruvsinghal/cuautograde,dhruvsinghal/cuautograde