Add LndHub db/models, and quick stats for admin views

app/models/lndhub_account.rb

@@ -0,0 +1,21 @@
+class LndhubAccount < LndhubBase
+  self.table_name = "accounts"
+  self.inheritance_column = :_type_disabled
+
+  has_many :ledgers, class_name: "LndhubAccountLedger",
+                     foreign_key: "account_id"
+
+  belongs_to :user, class_name: "LndhubUser",
+                    foreign_key: "user_id"
+
+  scope :current,  -> { where(type: "current") }
+  scope :outgoing, -> { where(type: "outgoing") }
+  scope :incoming, -> { where(type: "incoming") }
+  scope :fees,     -> { where(type: "fees") }
+
+  scope :with_balances, -> {
+    current.joins(:user).joins(:ledgers)
+      .group("accounts.id", "users.login")
+      .select("accounts.id, users.login, SUM(account_ledgers.amount) AS balance")
+  }
+end

app/models/lndhub_account_ledger.rb

@@ -0,0 +1,3 @@
+class LndhubAccountLedger < LndhubBase
+  self.table_name = "account_ledgers"
+end

app/models/lndhub_base.rb

@@ -0,0 +1,4 @@
+class LndhubBase < ActiveRecord::Base
+  self.abstract_class = true
+  establish_connection :lndhub
+end

app/models/lndhub_user.rb

@@ -0,0 +1,15 @@
+class LndhubUser < LndhubBase
+  self.table_name = "users"
+  self.inheritance_column = :_type_disabled
+
+  has_many :accounts, class_name: "LndhubAccount",
+                      foreign_key: "user_id"
+
+  belongs_to :user, class_name: "User",
+                    primary_key: "ln_account",
+                    foreign_key: "login"
+
+  def balance
+    accounts.current.first.ledgers.sum("account_ledgers.amount")
+  end
+end

app/models/user.rb

@@ -5,6 +5,11 @@ class User < ApplicationRecord
   has_many :invitations, dependent: :destroy
   has_many :donations, dependent: :nullify
 
+  has_one  :lndhub_user, class_name: "LndhubUser", inverse_of: "user",
+                         primary_key: "ln_account", foreign_key: "login"
+
+  has_many :accounts, through: :lndhub_user
+
   validates_uniqueness_of :cn
   validates_length_of :cn, :minimum => 3
   validates_uniqueness_of :email