Missing host to link to Rails heroku production - ruby-on-rails

Question

I have an app that I am trying to put onto production. When the user signs up they have an activation email that should be sent to their email accounts but I am getting stopped with this error:
ActionView::Template::Error(Missing host to link to! Please provide the :host parameter, set default_url_options[:host], or set :only_path to true)
The problem with this error is that I have everything set up correctly in my files. For example my production.rb file inside my environments folder looks like this:
config.action_mailer.raise_delivery_errors = true
config.action_mailer.delivery_method = :smtp
config.action_mailer.default_url_options = { :host => 'secret-everglades-54128.heroku.com'}
ActionMailer::Base.smtp_settings = {
:address => 'smtp.sendgrid.net',
:port => '587',
:authentication => :plain,
:user_name => ENV['SENDGRID_USERNAME'],
:password => ENV['SENDGRID_PASSWORD'],
:domain => 'heroku.com',
:enable_starttls_auto => true
}
My enviorments.rb file looks like this:
# Load the Rails application.
require_relative 'application'
# Initialize the Rails application.
Rails.application.initialize!
config.action_mailer.default_url_options = { :host => 'secret-everglades-54128.heroku.com'}
config.action_mailer.default_url_options = { :host => 'localhost:3000' }
This does not make any sense to me whatsoever, if anyone could shed some light on this problem I will be very great full.

Answer 1

The problem was that I had errors still concuring when I ran the command
git push heroku master
The problem was that I had my host set in the actually environment.rb file which wasn't needed so I removed that and once I did that I was able to get everything to work.