Improved surveys with specs

    -Created a javascript file called quvey.js which contains the scripts to
     handle the dynamic added of new questions.
    -Modified survey controller to handle more correctly the creation of
     surveys.
    -Modified datatype of field expired_at from survey table to datetime.
    -Deleted unnecessary file _question_possible_value_fields.html.erb.
    -Removed trailing spaces and added empty line to all files of project.
    -Added to the spec create_survey the test about creation questions.