Add heartbeat model, next_heartbeat_time and update_heartbeat_time on device registration

db/migrate/20151109071857_create_heartbeats.rb

@@ -0,0 +1,9 @@
+class CreateHeartbeats < ActiveRecord::Migration
+  def change
+    create_table :heartbeats do |t|
+      t.references :device, index: true, foreign_key: true
+
+      t.timestamps null: false
+    end
+  end
+end

db/migrate/20151109072450_add_heartbeats_details_to_devices.rb

@@ -0,0 +1,6 @@
+class AddHeartbeatsDetailsToDevices < ActiveRecord::Migration
+  def change
+    add_column :devices, :heartbeats_count, :integer, default: 0
+    add_column :devices, :last_heartbeat_recd_time, :datetime
+  end
+end