Added princples to the data base.

db/migrate/20220611182950_principle.rb

@@ -0,0 +1,4 @@
+class Principle < ActiveRecord::Migration[7.0]
+  def change
+  end
+end

db/migrate/20220611183116_create_principles.rb

@@ -0,0 +1,12 @@
+class CreatePrinciples < ActiveRecord::Migration[7.0]
+  def change
+    create_table :principles do |t|
+      t.references :caf, null: false, foreign_key: true
+      t.string :name
+      t.text :description
+
+      t.timestamps
+    end
+    add_index :principles, :name
+  end
+end