Rails and postgresql extensions

migration.rb

# It doesn't work...
class InstallTrigramContribPackage < ActiveRecord::Migration
  def up
    execute 'CREATE EXTENSION pg_trgm'
  end

  def down
    execute 'DROP EXTENSION pg_trgm'
  end
end

# ... this one does...
class InstallTrigramContribPackage < ActiveRecord::Migration
  def up
    execute 'CREATE EXTENSION IF NOT EXISTS pg_trgm'
  end

  def down
    execute 'DROP EXTENSION pg_trgm'
  end
end


# ... but this looks better
class InstallTrigramContribPackage < ActiveRecord::Migration
  def up
    enable_extension "pg_trgm"
  end
end