require "sequel"

DB = Sequel.sqlite
DB.create_table(:records) do
  primary_key :id
  String :column
end

data = 50_000.times.map { |i| Hash[column: "Column #{i}"] }

# =============================================================

DB[:records].multi_insert(data)

# Takes 2 seconds (like the SQL and activerecord-import versions), and it's a simple one-liner.