add source model

[cokernel]

See also #22.

[cokernel]

@rrmait0, there are a few problems with this pull request.

• The revised db/schema.rb is missing the records table entirely. I don't know why that is, but it needs to be fixed.
• Foreign keys should always be indexed, but the source_id column on records is not being indexed.
• :remove_column is not reversible, so the migration in db/migrate/20130821125926_remove_source_from_record.rb is incorrect. The list of methods that can appear in a change method is available in the Active Record Migrations guide. You can invoke the generator as rails g migration RemoveSourceFromRecord source to generate the correct migration.

[rrmait0]

@cokernel

Is there a way to just replace one file from the repository. I want to replace db/schema.rb from the most current one in master. Obviously, I do not want to loose my other changes.

[rrmait0]

I just replaced it by retrieving the latest one from github/uklibaries/metadata_editor/db/schema.rb

[cokernel]

It's not sufficient to checkout a fresh copy of db/schema.rb, because most migration actions end up touching the schema.

I recommend the following:

• From 8508cb6, run rake db:migrate, then git status. When I did this, the records table was restored in db/schema.rb.
• Edit db/migrate/20130821125926_remove_source_from_record.rb to be reversible, e.g.

class RemoveSourceFromRecord < ActiveRecord::Migration
  def up
    remove_column :records, :source
  end

  def down
    add_column :records, :source, :string
  end
end

• Rollback "Add source to record" by running rake db:rollback exactly once.
• Add the following line to the "Add source to record" migration:

     add_index :records, :source_id

• Run rake db:migrate.
• Commit all affected files and push.

That way we'll have the up-to-date schema in this branch.

[rrmait0]

I updated it but still there seems to be a problem with the records table missing for some reason. I'm not sure what's causing the table to be deleted.

[rrmait0]

The pull request should be ready now.

[cokernel]

Merging.