Fix linter errors

server/account_test.go

@@ -40,6 +40,7 @@ func TestRegisterUser(t *testing.T) {
 			http.MethodPost,
 			"/api/v1/user/register",
 			strings.NewReader(`{"password":"pass","email":"info@example.com","name":"Test"}`))
+		request.Header.Set("Content-Type", "application/json")
 		context := engine.NewContext(request, recorder)
 		if err != nil {
 			t.Errorf("error creating request: %s", err)