add homie to the gang when homie is created

db/migrate/20201007182916_add_name_to_gangs.rb

@@ -0,0 +1,5 @@
+class AddNameToGangs < ActiveRecord::Migration[5.2]
+  def change
+    add_column :gangs, :name, :text
+  end
+end

db/migrate/20201007183139_add_gang_relation_to_homies.rb

@@ -0,0 +1,5 @@
+class AddGangRelationToHomies < ActiveRecord::Migration[5.2]
+  def change
+    add_reference :homies, :gang
+  end
+end

db/migrate/20201007213411_add_initial_gang_and_connect_to_homies.rb

@@ -0,0 +1,15 @@
+class AddInitialGangAndConnectToHomies < ActiveRecord::Migration[5.2]
+  def up
+    # execute "INSERT INTO gangs SELECT 'name' WHERE NOT EXISTS (SELECT * FROM gangs)"
+    if Gang.count.zero?
+      Gang.create.save
+    end
+    gang = Gang.first
+
+    Homie.all.update(gang: gang)
+  end
+
+  def down
+    Homie.all.update(gang: nil)
+  end
+end