Basic Plaid Integration (#1433)

* Basic plaid data model and linking

* Remove institutions, add plaid items

* Improve schema and Plaid provider

* Add webhook verification sketch

* Webhook verification

* Item accounts and balances sync setup

* Provide test encryption keys

* Fix test

* Only provide encryption keys in prod

* Try defining keys in test env

* Consolidate account sync logic

* Add back plaid account initialization

* Plaid transaction sync

* Sync UI overhaul for Plaid

* Add liability and investment syncing

* Handle investment webhooks and process current day holdings

* Remove logs

* Remove "all" period select for performance

* fix amount calc

* Remove todo comment

* Coming soon for investment historical data

* Document Plaid configuration

* Listen for holding updates

app/models/concerns/syncable.rb

@@ -0,0 +1,33 @@
+module Syncable
+  extend ActiveSupport::Concern
+
+  included do
+    has_many :syncs, as: :syncable, dependent: :destroy
+  end
+
+  def syncing?
+    syncs.where(status: [ :syncing, :pending ]).any?
+  end
+
+  def sync_later(start_date: nil)
+    new_sync = syncs.create!(start_date: start_date)
+    SyncJob.perform_later(new_sync)
+  end
+
+  def sync(start_date: nil)
+    syncs.create!(start_date: start_date).perform
+  end
+
+  def sync_data(start_date: nil)
+    raise NotImplementedError, "Subclasses must implement the `sync_data` method"
+  end
+
+  def sync_error
+    latest_sync.error
+  end
+
+  private
+    def latest_sync
+      syncs.order(created_at: :desc).first
+    end
+end