How can I get a slices new index after a goroutine channel has mutated the slice?

I'm wondering how I can get an elements new index in a slice, I have a function that gets applications from a database, and queries for certain ones (for filtering) but when I query for ones and I get ones I don't need, I'm trying to remove them from the slice so that only the wanted ones make it to the view. It's working but I'm having a problem with the index's in the goroutines are the older index's so when it trys to remove the element from the slice it panics: Anyways here is my code:

// ListApplications will list the applications
func ListApplications(w http.ResponseWriter, r *http.Request) {
	session := common.Sesh(r)
	urlParse, err := url.ParseRequestURI(r.RequestURI)
	vals := urlParse.Query()

	if err != nil {
		log.Println(err)
	}
	if lvl, ok := session.Values["user_level"]; !ok || lvl.(int) < 3 {
		http.Redirect(w, r, "/", 401)
		return
	}

	db := common.Db()

	type UserResp struct {
		Action string
		I      int
		User   common.User
	}
	apps := []common.Application{}
	resp := make(chan UserResp)
	db.Order("accepted asc").Order("created_at asc").Find(&apps)
	var wg sync.WaitGroup
	for i, app := range apps {
		wg.Add(1)
		go func(i int, app common.Application) {
			user := common.User{}
			if vals.Get("class") != "" {
				db.Preload("Characters", "character_class = ?", vals.Get("class")).Model(&app).Related(&user)
				if len(user.Characters) == 0 {
					resp <- UserResp{"remove", i, user}
				} else {
					resp <- UserResp{"add", i, user}
				}
				wg.Done()
				return
			}

			db.Preload("Characters").Model(&app).Related(&user)
			log.Println(user)
			resp <- UserResp{"add", i, user}
			wg.Done()
		}(i, app)
	}

	go func() {
		wg.Wait()
		close(resp)
	}()

	for user := range resp {
		switch user.Action {
		case "add":
			apps[user.I].User = user.User
		case "remove":
		log.Println(len(apps), user.I)
			apps = append(apps[:user.I], apps[user.I+1:]...)
		}
	}

	common.View(w, r, "/application/list", &struct {
		Title string
		Apps  []common.Application
	}{"Viewing Applications", apps})
}

The for user := range resp is where I'm trying to delete under the "remove" action. But like I said, the index getting passed through on the channel is out dated sometimes so how can I maintain a persistent index in my goroutines

Don't range over a slice if you want to remove elements from it.

Instead, loop over the slice by index:

// Removes 2 from slice.
slice := []int{1,2,3}
for i := 0; i < len(slice); i++ {
	if slice[i] == 2 {
		slice = append(slice[:i], slice[i+1:]...)
		i--
	}
}
fmt.Println(slice) // [1 3]

The point is bringing the index cursor back by one (so it won't go forward) after you've removed the current element.