20121210170504_create_pizzas.rb

class CreatePizzas < ActiveRecord::Migration
  def change
    create_table :pizzas, :options => 'ENGINE=MyISAM' do |t|
      t.string :awesome
      t.timestamps
    end

    add_index :pizzas, :awesome, type: 'FULLTEXT'
  end

end

20130327170545_create_yolos.rb

class CreateYolos < ActiveRecord::Migration
  def change
    create_table :yolos do |t|
      t.string :swag
      t.timestamps
    end

    add_index "yolos", ["swag"], name: "you_only_live_once_bro"
  end
end

debug_info.rb

        def add_index_options(table_name, column_name, options = {})
          column_names = Array(column_name)
          index_name   = index_name(table_name, column: column_names)

          if Hash === options # legacy support, since this param was a string
            puts "add_index_options(#{table_name.inspect}, #{column_name.inspect}, #{options.inspect})"
            puts "options class: #{options.class}"
            puts "options[:type] = #{options[:type]}"
            puts "options[:name] = #{options[:name]}"

            options = options.symbolize_keys

            puts "options[:type] = #{options[:type]}"
            puts "options[:name] = #{options[:name]}"

            options.assert_valid_keys(:unique, :order, :name, :where, :length, :internal, :using, :algorithm, :type)

            index_type = options[:unique] ? "UNIQUE" : ""
            index_type = options[:type].to_s if options.key?(:type)
            index_name = options[:name].to_s if options.key?(:name)
            max_index_length = options.fetch(:internal, false) ? index_name_length : allowed_index_name_length

            if index_algorithms.key?(options[:algorithm])
              algorithm = index_algorithms[options[:algorithm]]
            elsif options[:algorithm].present?
              raise ArgumentError.new("Algorithm must be one of the following: #{index_algorithms.keys.map(&:inspect).join(', ')}")
            end

            using = "USING #{options[:using]}" if options[:using].present?

            if supports_partial_index?
              index_options = options[:where] ? " WHERE #{options[:where]}" : ""
            end
          else
            if options
              message = "Passing a string as third argument of `add_index` is deprecated and will" +
                " be removed in Rails 4.1." +
                " Use add_index(#{table_name.inspect}, #{column_name.inspect}, unique: true) instead"

              ActiveSupport::Deprecation.warn message
            end

            index_type = options
            max_index_length = allowed_index_name_length
            algorithm = using = nil
          end

          if index_name.length > max_index_length
            raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' is too long; the limit is #{max_index_length} characters"
          end
          if index_name_exists?(table_name, index_name, false)
            raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' already exists"
          end
          index_columns = quoted_columns_for_index(column_names, options).join(", ")

          [index_name, index_type, index_columns, index_options, algorithm, using]
        end

migrate_output

==  CreatePizzas: migrating ===================================================
-- create_table(:pizzas, {:options=>"ENGINE=MyISAM"})
   -> 0.0085s
-- add_index(:pizzas, :awesome, {:type=>"FULLTEXT"})
add_index_options("pizzas", :awesome, {:type=>"FULLTEXT"})
options class: Hash
options[:type] = FULLTEXT
options[:name] = 
options[:type] = FULLTEXT
options[:name] = 
   -> 0.0040s
==  CreatePizzas: migrated (0.0127s) ==========================================

==  CreateYolos: migrating ====================================================
-- create_table(:yolos)
   -> 0.0035s
-- add_index("yolos", ["swag"], {:name=>"you_only_live_once_bro"})
add_index_options("yolos", ["swag"], {:name=>"you_only_live_once_bro"})
options class: Hash
options[:type] = 
options[:name] = you_only_live_once_bro
options[:type] = 
options[:name] = you_only_live_once_bro
   -> 0.0074s
==  CreateYolos: migrated (0.0111s) ===========================================

schema.rb

  create_table "pizzas", force: true do |t|
    t.string   "awesome"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

  add_index "pizzas", ["awesome"], name: "index_pizzas_on_awesome", type: :fulltext

  create_table "yolos", force: true do |t|
    t.string   "swag"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

  add_index "yolos", ["swag"], name: "you_only_live_once_bro", using: :btree