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

db/migrate/20190818135624_add_color_to_booth_group.rb

@@ -0,0 +1,5 @@
+class AddColorToBoothGroup < ActiveRecord::Migration[5.2]
+  def change
+    add_column :booth_groups, :color, :string, default: '#000000'
+  end
+end