Add migrations

db/migrate/20190818124036_create_booth_group.rb

@@ -0,0 +1,11 @@
+class CreateBoothGroup < ActiveRecord::Migration[5.2]
+  def change
+    create_table :booth_groups do |t|
+      t.references :program
+      t.string :name, null: false
+
+      t.timestamps
+    end
+    add_reference :booths, :booth_group, index: true
+  end
+end