feat(api): create template

Add template table to the database
Create controller function to check if user has template, and create it
in the database
Made universal jwt.Claims of user data retrieval function

backend/models/template/template.go

@@ -0,0 +1,70 @@
+package template
+
+import (
+	"backend/db"
+	"context"
+	"time"
+)
+
+type Template struct {
+	ID        int
+	UserID    int
+	Name      string
+	Template  string
+	CreatedAt time.Time
+}
+
+func Create(name string, template string, userId float64) error {
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+	defer cancel()
+
+	// build query
+	query := `INSERT INTO templates (name, template, user_id) VALUES ($1, $2, $3)`
+
+	// execute query
+	_, err := db.Pool.Exec(ctx, query, name, template, userId)
+
+	return err
+}
+
+// * will follow the pointer to its value
+// If user id is 0, then we will search only by name
+func FindByName(name string, userId float64) ([]Template, error) {
+	// Create timeout context
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+	defer cancel()
+
+	// Build query and execute
+	query := `SELECT * FROM templates WHERE "name" = $1`
+	args := []any{name}
+
+	// Do we need to search by user id?
+	if userId > 0 {
+		query += " AND user_id = $2"
+		args = append(args, userId)
+	}
+
+	rows, err := db.Pool.Query(ctx, query, args...)
+	// Query executes query instantly, and returns error instantly
+	// Not like QueryRow, which executes query only on row.Scan
+	if err != nil {
+		return nil, err
+	}
+	// need to tell database to close the rows connection
+	// and free up resources
+	defer rows.Close()
+
+	// Prepeare results now
+	var results []Template
+	for rows.Next() {
+		var t Template
+		if err := rows.Scan(&t.ID, &t.UserID, &t.Name, &t.Template, &t.CreatedAt); err != nil {
+			return nil, err
+		}
+
+		results = append(results, t)
+	}
+
+	// Give pointer back
+	return results, nil
+}