A little lib to cause migrations to skip duplicates instead of failing.

migration_skip_duplicates.rb

class MyCompany::Migration < ActiveRecord::Migration
  def self.add_column(*args)
    begin
      super
    rescue => e
      if e.message =~ /Duplicate/
        puts "WARNING, a migration line was skipped due to it already existing: #{e.message}"
      else
        raise e
      end
    end
  end
  def self.rename_column(*args)
    begin
      super
    rescue => e
      if e.message =~ /Duplicate/
        puts "WARNING, a migration line was skipped due to it already existing: #{e.message}"
      else
        raise e
      end
    end
  end
  def self.add_index(*args)
    begin
      super
    rescue => e
      if e.message =~ /Duplicate/
        puts "WARNING, a migration line was skipped due to it already existing: #{e.message}"
      else
        raise e
      end
    end
  end
  def self.create_table(*args, &block)
    begin
      super
    rescue => e
      if e.message =~ /Duplicate/
        puts "WARNING, a migration line was skipped due to it already existing: #{e.message}"
      else
        raise e
      end
    end
  end

end