railroad-database problem

reporting.rb
class Reporting < ActiveRecord::Base

connection = "legacy_#{ENV['RAILS_ENV']}"

establish_connection connection.to_sym

end

[snip]

How to make railroad understand that reporting.rb is not a table but
just a connection.

I believe this is a pure rails problem. You need to set self.abstract_class = true in the Reporting class so that rails knows that there is no matching table.

Fred