refactors signature sheets

db/migrate/20161214212918_create_signature_sheets.rb

@@ -3,7 +3,7 @@ class CreateSignatureSheets < ActiveRecord::Migration
     create_table :signature_sheets do |t|
       t.references :signable, polymorphic: true
       t.text :document_numbers
-      t.boolean :processed
+      t.boolean :processed, default: false
       t.references :author
       t.timestamps
     end

db/migrate/20161214233817_create_signatures.rb

@@ -4,7 +4,7 @@ class CreateSignatures < ActiveRecord::Migration
       t.references :signature_sheet
       t.references :user
       t.string :document_number
-      t.string :status, default: nil
+      t.boolean :verified, default: false
       t.timestamps
     end
   end