feat: Add Platform APIs (#1456)

db/migrate/20201123195011_create_platform_apps.rb

@@ -0,0 +1,8 @@
+class CreatePlatformApps < ActiveRecord::Migration[6.0]
+  def change
+    create_table :platform_apps do |t|
+      t.string :name, null: false
+      t.timestamps
+    end
+  end
+end