Added migration file for actions table

Author: ch00z00

backend/db/migrations/000003_create_actions_table.down.sql

@@ -0,0 +1,2 @@
+-- This migration will drop the actions table if it exists
+DROP TABLE IF EXISTS actions;

backend/db/migrations/000003_create_actions_table.up.sql

@@ -0,0 +1,12 @@
+CREATE TABLE actions (
+    id INT AUTO_INCREMENT PRIMARY KEY,
+    user_id VARCHAR(36) NOT NULL,
+    goal_id INT NOT NULL,
+    content TEXT NOT NULL,
+    completed_at TIMESTAMP NULL,
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+    INDEX idx_user_id_action (user_id),
+    INDEX idx_goal_id_action (goal_id),
+    FOREIGN KEY (goal_id) REFERENCES goals(id) ON DELETE CASCADE
+);