Add basic functionality

db/migrate/20230924015422_create_people.rb

@@ -2,6 +2,8 @@ class CreatePeople < ActiveRecord::Migration[7.0]
   def change
     create_table :people do |t|
       t.string :name, null: false
+      t.date :birth_day, null: false
+      t.references :birth_country, null: false, foreign_key: { to_table: :countries }
 
       t.timestamps
     end

db/migrate/20230924015803_create_admissions.rb

@@ -3,6 +3,8 @@ class CreateAdmissions < ActiveRecord::Migration[7.0]
     create_table :admissions do |t|
       t.references :country, null: false, foreign_key: true
       t.references :person, null: false, foreign_key: true
+      t.references :previous, null: true, foreign_key: { to_table: :admissions }
+
       t.date :arrived_on, null: false
 
       t.timestamps