Feature: Feature flags on account (#814) (#815)

* Feature: Feature flags on account (#814)
* Added the new column on account model for managing feature flags
* Added the inbound email flag
* Locked the settings of this eature in account settings based on this
* Encapsulated the feature flaging as a concern. With this, we can re-use the same concern if we introduce this in other models like user or inbox or so.
* Added the features in the account api

* Changed Rails/FilePath style - rubocop issue

* Revert "Changed Rails/FilePath style - rubocop issue"

This reverts commit 3a42d3b9c9b3a2fde8bc7256fd704b6fcaf54040.

* Disabling rubocop on codeclimate as we already have this in CICD

db/migrate/20200503151130_add_account_feature_flag.rb

@@ -0,0 +1,5 @@
+class AddAccountFeatureFlag < ActiveRecord::Migration[6.0]
+  def change
+    add_column :accounts, :feature_flags, :integer, index: true, default: 0, null: false
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2020_04_29_082655) do
+ActiveRecord::Schema.define(version: 2020_05_03_151130) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "pgcrypto"
@@ -46,6 +46,7 @@ ActiveRecord::Schema.define(version: 2020_04_29_082655) do
     t.string "domain", limit: 100
     t.string "support_email", limit: 100
     t.integer "settings_flags", default: 0, null: false
+    t.integer "feature_flags", default: 0, null: false
   end
 
   create_table "action_mailbox_inbound_emails", force: :cascade do |t|