Handling POST for logs with multiple data

Handles POST with multiple records to save in the database - also added
test the same.
Adding the excel sheet with the board data

This is just for future reference - the board-insert query was generated
from here.
Renaming UserName to Login in the url format

/logs/{username} is now => /logs/{login} - it is the login of the user
that is sent, so this is more accurate. The change is made mainly to
maintain same nomenclature across code-base rather than creating
confusion.