Each migration should be contained in a separate file because they each should make incremental schema changes.  For example, say someone installs `active_nutrition` v0.6.0 and runs migrations.  Their database now has a specific schema, namely the one that corresponds with Sr24.  When the next version of `active_nutrition` comes out (v.0.6.1) with an update to Sr25, we can't expect that user to replace their whole existing schema with a new one, so we offer incremental schema updates (migrations).

Move your update to Sr25 into a separate file, lib/active_nutrition/migrations_00000000003_sr_25.rb.  It might contain something like this:

```ruby
module ActiveNutrition
  module Migrations
    class Sr25 < ActiveRecord::Migration
      change_column :abbrev, :Msre_Desc, :string, :limit => 100
    end
  end
end
```