Fix SystemStackError in schema_dumper.rb in combination with activerecord-multi-tenant

[Laykou]

When using https://github.com/citusdata/activerecord-multi-tenant gem, it also overrides the SchemaDumper. This gem uses alias method instead of super.

Reference:
https://github.com/citusdata/activerecord-multi-tenant/blob/0ac43aa98334a29ed3e5b33e0bcc5ee281f97254/lib/activerecord-multi-tenant/migrations.rb#L86

strong_migrations in combination with this gem created following issue:

SystemStackError: stack level too deep (SystemStackError)
.../gems/strong_migrations-1.8.0/lib/strong_migrations/schema_dumper.rb:6:in `new'
.../gems/strong_migrations-1.8.0/lib/strong_migrations/schema_dumper.rb:6:in `initialize'
.../gems/activerecord-multi-tenant-2.4.0/lib/activerecord-multi-tenant/migrations.rb:93:in `initialize'
.../gems/strong_migrations-1.8.0/lib/strong_migrations/schema_dumper.rb:6:in `initialize'
.../gems/activerecord-multi-tenant-2.4.0/lib/activerecord-multi-tenant/migrations.rb:93:in `initialize'
.../gems/strong_migrations-1.8.0/lib/strong_migrations/schema_dumper.rb:6:in `initialize'

I figured out using the prepended with the alias method instead avoided the issue in overriding the initialize method by multiple gems

[ankane]

Hi @Laykou, thanks for the PR, but I think it's better for conflicting gems to switch to Module#prepend (#129).

[Laykou]

@ankane Thank you, I may not be that fluent in this "Ruby overriding" world. So you're saying using:

ActiveRecord::SchemaDumper.prepend(StrongMigrations::SchemaDumper)

like you do in this gem is preferred/better option rather than monkey pathing:

module ActiveRecord
  class SchemaDumper
    alias initialize_without_citus initialize

    def initialize(connection, options = {})
      # ... calling 
    end
  end
end

that is done in the other gem? And the root cause of the issue is this monkey patching.
Calling super when using prepend is the correct way, right?

Thank you for your insights

[ankane]

Yes, I think Module#prepend is the better pattern.