Golang，mgo更新用户详细信息

I have been having some trouble updating a user on a mongodatabase. Basically I want to select the user by username and than edit its details. I am using Gorilla Mux and mgo to connect with MongoDB.

Here is the code:

func ViewUserHandler(w http.ResponseWriter, r *http.Request) {
    vars := mux.Vars(r)
    username := vars["username"]
    session, err := mgo.Dial("mongodb://DATABASE_URL")

    if err != nil {
        panic(err)
    }

    defer session.Close()
    session.SetMode(mgo.Monotonic, true)
    c := session.DB("studnet").C("user")

    result := Person{}
    // get the user_id using a hidden field when clicked using javascript
    err = c.Find(bson.M{"name": username}).One(&result)
    if err != nil {
        log.Fatal(err)
    }

    if r.Method == "GET" {
        t, _ := template.ParseFiles("profile.html")
        t.Execute(w, result)
    }
    // update the user profile details
    if r.Method == "POST" {
        r.ParseForm()

        // TODO : update the user
        selectedUser := bson.M{"name": username}
        updatedUser := bson.M{"$set": bson.M{
            "Name":      r.Form["username"][0],
            "Gender":    r.Form["gender"][0],
            "Age":       r.Form["age"][0],
            "CreatedAt": time.Now(),
        }}
        err = c.Update(selectedUser, updatedUser)

        if err != nil {
            panic(err)
        }
        http.Redirect(w, r, "/view/"+username, 301)
    }
}

Well I see at least one problem a that is the case sensitive queries. So if your struct uses lowercase keys in json, you must use a lowercase one.

// This shoud match 
// against the "Name" property
selectedUser := bson.M{"Name": username}

updatedUser := bson.M{"$set": bson.M{
                "Name":      r.Form["username"][0],
                "Gender":    r.Form["gender"][0],
                "Age":       r.Form["age"][0],
                "CreatedAt": time.Now(),
 }}

data := model.Data {
            Name:      r.Form["username"][0],
            Gender:    r.Form["gender"][0],
            Age:       r.Form["age"][0],
            CreatedAt:  time.Now(),
        }

selectedUser := bson.M{"name": username}
updatedUser := bson.M{"$push": bson.M{"user": bson.M{"$each": []model.User{data}}}}
err = c.Update(selectedUser, updatedUser)

This will update the user array against matching username. It would be great if you can share the struct too. I have answered with the assumptions.