Serve compiled front from the same application

also add embedded build for production

internal/apitest/post_book_test.go

@@ -68,7 +68,7 @@ func testPostBookHandler(t *testing.T, bookJson string, expectedCode int) {
 	w := httptest.NewRecorder()
 
 	token := testutils.ConnectDemoUser(router)
-	req, _ := http.NewRequest("POST", "/book",
+	req, _ := http.NewRequest("POST", "/ws/book",
 		strings.NewReader(string(bookJson)))
 	req.Header.Add("Authorization", fmt.Sprintf("Bearer %s", token))
 	router.ServeHTTP(w, req)