Implement POST task (#28)

Closes #21

Reviewed-on: #28

backend/db.go

@@ -150,3 +150,35 @@ func (db *Db) DeleteGoal(userId int, goalId int) error {
 
 	return nil
 }
+
+func (db *Db) CreateTask(task *CreateTaskRequest) (int, error) {
+	tx, err := db.db.Begin()
+	if err != nil {
+		return 0, err
+	}
+	defer tx.Rollback()
+
+	// Insert the new task
+	err = tx.Query("insert into tasks (name, reward, assigned) values (?, ?, ?)").
+		Bind(task.Name, task.Reward, task.Assigned).
+		Exec()
+
+	if err != nil {
+		return 0, err
+	}
+
+	// Get the last inserted ID
+	var lastId int
+	err = tx.Query("select last_insert_rowid()").ScanSingle(&lastId)
+	if err != nil {
+		return 0, err
+	}
+
+	// Commit the transaction
+	err = tx.Commit()
+	if err != nil {
+		return 0, err
+	}
+
+	return lastId, nil
+}