postgre_sql_database_tasks monkey patch to exclude schemas from dump.

postgre_sql_database_tasks.rb

module ActiveRecord
  module Tasks # :nodoc:
    class PostgreSQLDatabaseTasks # :nodoc:
      def structure_dump(filename)
        set_psql_env

        puts "The monkeypatch located in #{__FILE__} should be removed when upgrading to Rails 5.0"
        search_path = nil # Dump all schemas

        unless search_path.blank?
           search_path = search_path.split(",").map{|search_path_part| "--schema=#{Shellwords.escape(search_path_part.strip)}" }.join(" ")
        end

        command = "pg_dump --exclude-schema='tenant*' -i -s -x -O -f #{Shellwords.escape(filename)} #{search_path} #{Shellwords.escape(configuration['database'])}"
        raise 'Error dumping database' unless Kernel.system(command)

        File.open(filename, "a") { |f| f << "SET search_path TO #{connection.schema_search_path};\n\n" }
      end
    end
  end
end