Some advice, concentrate on one problem at a time when asking for
help. By asking another two questions in the same thread you have
just complicated the situation and no-one will know which problem to
respond to. So here concentrate on sorting your google authentication
problem. To ask the other questions start new threads with
appropriate subject lines. Also it is no good asking people to go
and look at an app you have cloned, no-one has the time for that. You
must ask targeted questions about specific issues you are having and
show us the specific bit of code that you are having trouble with.
As a RoR novice myself, I can tell you that you are NOT doing your home
work before asking questions ... you are NOT putting in the necessary
time, patience and resolve required to find a solution for YOURSELF ...
However, in about 15 secs I found on the internet a possible hint to
what your problem is
The following snippets are a working example of setting up ActionMailer/Devise using a domain email account hosted on Google Apps with Rails 4.2/Ruby 2.2.1. This is different than using regular Gmail account which only requires you to go into the account settings and turn on “Access for less secure apps”. This setting isn’t available for the former. You must use SSL instead.
I would also advise using mailcatcher in development...you don't need gmail in development -- only maybe when you deploy to test production settings...