Does not work with Rails 6

[ELepolt]

Start up a new rails app

# Note: Not exact

rails _6.0.0.0_ new rails6

# Add dossier to gemfile
bundle install
rails generate scaffold Post name:string title:string content:text

rails c
Post.all

The final command spits out an error: ArgumentError (wrong number of arguments (given 2, expected 1))

Here's a working repo to reproduce the issue. You can swap between rails 6 and rails 5 to see that it is working in 5.
https://github.com/ELepolt/rails6-dossier

[n00dle]

The underlying issue is that dossier depends on the arel gem, but that gem has become part of ActiveRecord. When AR tries to run, it picks up the separate arel gem. The two arel versions have diverged to the point of incompatibility, resulting in the ArgumentError. The stacktrace looks something like this:

ArgumentError: wrong number of arguments (given 2, expected 1)
gemdir/arel-9.0.0/lib/arel/visitors/to_sql.rb:73:in `compile'
gemdir/activerecord-6.0.6.1/lib/active_record/connection_adapters/abstract/database_statements.rb:35:in `to_sql_and_binds'