Added metadata to Issue

Created by: joel-rightshift

We needed a field on Issue that could hold arbitrary data. To enable this, we added a metadata field. The change itself it rather simple

db/migrate/20140701130425_add_metadata_to_issues.rb

+class AddMetadataToIssues < ActiveRecord::Migration
+  def change
+    add_column :issues, :metadata, :string
+  end
+end