removing deprecation warning from rails 5

README.md

@@ -460,7 +460,7 @@ Devise allows you to set up as many Devise models as you want. If you want to ha
 create_table :admins do |t|
   t.string :email
   t.string :encrypted_password
-  t.timestamps
+  t.timestamps, null: false
 end
 
 # Inside your Admin model

lib/generators/active_record/templates/migration.rb

@@ -7,7 +7,7 @@ class DeviseCreate<%= table_name.camelize %> < ActiveRecord::Migration
       t.<%= attribute.type %> :<%= attribute.name %>
 <% end  -%>
 
-      t.timestamps
+      t.timestamps, null: false
     end
 
     add_index :<%= table_name %>, :email,                unique: true

lib/generators/active_record/templates/migration_existing.rb

@@ -8,7 +8,7 @@ class AddDeviseTo<%= table_name.camelize %> < ActiveRecord::Migration
 <% end  -%>
 
       # Uncomment below if timestamps were not included in your original model.
-      # t.timestamps
+      # t.timestamps, null: false
     end
 
     add_index :<%= table_name %>, :email,                unique: true