add healthcheck route

cmd/api/errors.go

@@ -0,0 +1,24 @@
+package main
+
+import "net/http"
+
+func (app *application) logError(r *http.Request, err error) {
+	app.slogger.Error(err.Error(), "request_method", r.Method, "request_url", r.URL.String())
+}
+
+func (app *application) errorResponse(w http.ResponseWriter, r *http.Request, status int, message any) {
+	env := envelope{"error": message}
+
+	err := app.writeJSON(w, status, env, nil)
+	if err != nil {
+		app.logError(r, err)
+		w.WriteHeader(500)
+	}
+}
+
+func (app *application) serverErrorResponse(w http.ResponseWriter, r *http.Request, err error) {
+	app.logError(r, err)
+
+	message := "the server encountered a problem and could not process your request"
+	app.errorResponse(w, r, http.StatusInternalServerError, message)
+}