app/models/project.rb

@@ -1,3 +1,5 @@
 class Project < ApplicationRecord
-    has_many :tasks
+    has_many :tasks, dependent: :destroy
+
+    validates :project_name, :description, presence: true
 end

app/models/task.rb

@@ -2,4 +2,6 @@ class Task < ApplicationRecord
     belongs_to :project
 
     enum :status, { to_do: 0, in_progress: 1, done: 2 }
+
+    validates :title, presence: true
 end