activated the 'bcrypt-ruby' gem.
updated Gemfile.lock with 'bcrypt-ruby' gem.
created scaffold of user.
added guard-rspec, spring gems to Gemfile.
removed unexpected spaces.
added Guardfile created by `guard init rspec` command.
using guard with spring.
added some validations to user attributes.
wrote some specs of user model.
configured to run simplecov with rspec.
ignore the coverage reports.