store_new_submissions copies new files from the subdirectories of
to the respective subdirectories of
Each team has a subdirectory.
The copied files in
hist_dir are prefixed with the last modification date for uniqueness.
A file is considered new if its name and last modification time is new, i.e not present
The files must match
pattern regular expression and must not
throw errors or warnings when given to the
store_new_submissions(submissions_dir = "submissions", hist_dir = "history", deadline, pattern = ".*\\.csv$", valid_fun)
store_new_submissions returns a named list of errors or warnings catched during the process.
Members named after the team names are lists with members named after the file
that throws an error which contain the error object.