Added documentation on enabling two-factor authentication to go with
the enhancement patch submitted on web2py github (#431)
Update 13.markmin

The permissions need to change from `433` to `443` in order for the password to work. See glenn's note here: https://www.pythonanywhere.com/forums/topic/902/#id_post_6553
minor correction from villas via web2py group 2014-06-22
Update 03.markmin

Wrong use o  request.vars
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Substantial rewrite of the first part of the DAL chapter, adding better documentation for DAL, Tables and Fields.
clarification of on_defines example
Merge pull request #219 from steven-mercatante/patch-1

Update 13.markmin
Merge pull request #220 from timrichardson/ch3erratum

minor correction from villas via web2py group 2014-06-22
Merge pull request #221 from mabeett/patch-1

Update 03.markmin
Merge pull request #222 from mabeett/patch-2

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Merge pull request #223 from timrichardson/db_quoting

Substantial rewrite of the first part of the DAL chapter, adding better ...
added NDB comment
Update 09.markmin

Added a note in the extra fields section saying you need to clear sessions if you want the changes to be reflected in auth.user
more small changes to Chapter 06
typo (stray line)
gitignore tweaks
some improvements to the DAL chapter: about using DAL standalone, more about commit in modules
Merge pull request #202 from ortgit/enhancement/two_step_authentication

Added documentation on enabling two-factor authentication
Merge pull request #224 from leonelcamara/master

Update 09.markmin