fixed #706 : handling fresh/new user scenario, creates Notebook 1 by default

Assigning the new notebook number based on availability and create 'Notebook 1' in case of new/fresh user login.
What does this line do?  Maybe it is time to look at how promises work.  I don't see any reason to handle rejections (exceptions) of `find_next_copy_name`, if that is what this does.
https://github.com/petkaantonov/bluebird/blob/master/API.md#thenfunction-fulfilledhandler--function-rejectedhandler----promise