Feature: Introduce Super Admins (#705)

* Feature: Introduce Super Admins

- added new devise model for super user
- added administrate gem
- sample dashboards for users and accounts

Co-authored-by: Pranav Raj Sreepuram <pranavrajs@gmail.com>

app/models/super_admin.rb

@@ -0,0 +1,27 @@
+# == Schema Information
+#
+# Table name: super_admins
+#
+#  id                  :bigint           not null, primary key
+#  current_sign_in_at  :datetime
+#  current_sign_in_ip  :inet
+#  email               :string           default(""), not null
+#  encrypted_password  :string           default(""), not null
+#  last_sign_in_at     :datetime
+#  last_sign_in_ip     :inet
+#  remember_created_at :datetime
+#  sign_in_count       :integer          default(0), not null
+#  created_at          :datetime         not null
+#  updated_at          :datetime         not null
+#
+# Indexes
+#
+#  index_super_admins_on_email  (email) UNIQUE
+#
+class SuperAdmin < ApplicationRecord
+  # Include default devise modules. Others available are:
+  # :confirmable, :lockable, :timeoutable, :trackable and :omniauthable
+  devise :database_authenticatable, :trackable, :rememberable, :validatable
+
+  include AccessTokenable
+end