add completed submitters and documents

app/models/completed_document.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: completed_documents
+#
+#  id           :bigint           not null, primary key
+#  sha256       :string           not null
+#  created_at   :datetime         not null
+#  updated_at   :datetime         not null
+#  submitter_id :bigint           not null
+#
+# Indexes
+#
+#  index_completed_documents_on_sha256        (sha256)
+#  index_completed_documents_on_submitter_id  (submitter_id)
+#
+class CompletedDocument < ApplicationRecord
+  belongs_to :submitter
+end