feat: add circulating supply to daily statistics

app/models/daily_statistic.rb

@@ -40,4 +40,5 @@ class DailyStatistic < ApplicationRecord
 #  daily_dao_withdraw           :decimal(30, )
 #  circulation_ratio            :decimal(, )
 #  total_supply                 :decimal(30, )
+#  circulating_supply           :decimal(, )
 #

db/migrate/20200427101449_add_circulating_supply_to_daily_statistic.rb

@@ -0,0 +1,5 @@
+class AddCirculatingSupplyToDailyStatistic < ActiveRecord::Migration[6.0]
+  def change
+    add_column :daily_statistics, :circulating_supply, :decimal
+  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_27_073824) do
+ActiveRecord::Schema.define(version: 2020_04_27_101449) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -194,6 +194,7 @@
     t.decimal "daily_dao_withdraw", precision: 30
     t.decimal "circulation_ratio"
     t.decimal "total_supply", precision: 30
+    t.decimal "circulating_supply"
   end
 
   create_table "dao_contracts", force: :cascade do |t|