I've been training Lightning Components by myself and I'm creating a modal that shows the user a video. The user has the option to tick a checkbox which prevents the modal to show up again. My question is: how can I change the value from an object (from false to trye) when the user clicks this checkbox?
Controller
({
    openModal: function (component, event, helper) {
        helper.getUser(component);
    },
    closeButton: function (component) {
        component.set("v.modal", false);
    },
    saveCheckboxChoice: function (component, event) {
        var isChecked = component.find("checkbox");
        var result = isChecked.get("v.value");
        if (result == true) {
            var userId = $A.get("$SObjectType.CurrentUser.Id");
            //component.set(userId.user.Modal__c, true);
            alert('User ID is: ' + userId);
        }
    },    
})Helper
({
    getUser: function (component) {
        component.set("v.modal", true);
        var act = component.get("c.apexController");
        act.setCallback(this, function (a) {
            component.set("v.userList", a.getReturnValue());
        });
    $A.enqueueAction(act);
    }
})
Apex Controller
public with sharing class apexController {
    @AuraEnabled
    public static List<User> apexController() {
        List<User> result = [SELECT Name, Modal__c FROM User WHERE ID=:userInfo.getUserId()];
        return result;
    }
}Component
<aura:component implements="flexipage:availableForAllPageTypes" access="global" controller="apexController">
    <aura:handler name="init" action="{!c.openModal}" value="{!this}" />
    <aura:attribute name="modal" type="boolean" default="true" />
    <aura:attribute name="value" type="boolean" default="false" />
    <aura:attribute name="userList" type="list" />
    <!-- Defines if the modal will be shown -->
    <aura:if isTrue="{!v.modal}">
        <!-- Start -->
        <section role="dialog" class="slds-modal slds-fade-in-open">
            <div class="slds-modal__container">
                <!-- Modal Header -->
                <header class="slds-modal__header">
                    <h2 class="slds-text-heading_medium slds-hyphenate"> {!$Label.c.welcomeLabel} </h2>
                    <br />
                    <p> {!$Label.c.customLabel} </p>
                </header>
                <!-- Modal Body -->
                <div class="slds-modal__content slds-p-around_medium">
                    <section class="slds-align_absolute-center" style="height:auto">
                        <!-- <img src="ltm.jpg"> -->
                        <iframe width="560" height="315" src="https://www.youtube.com/embed/qxJU4PYuNP0"
                            allowfullscreen="true"></iframe>
                    </section>
                </div>
                <table class="slds-table slds-table_bordered slds-table_cell-buffer">
                    <tr>
                        <th>Name of the User </th>
                        <th>Modal Permission </th>
                    </tr>
                    <aura:iteration items="{!v.userList}" var="prd">
                        <tr>
                            <td>
                                {!prd.Name}
                            </td>
                            <td>{!prd.Modal__c} </td>
                        </tr>
                    </aura:iteration>
                </table>
                <!-- Modal Footer -->
                <footer class="slds-modal__footer">
                    <lightning:button variant="brand" label="Fechar" onclick="{!c.closeButton}" />
                    <div class="slds-form-element">
                        <div class="slds-form-element__control">
                            <div>
                                <ui:inputCheckbox class="myCheckbox" aura:id="checkbox" change="{!c.saveCheckboxChoice}"
                                    label="Não desejo ver esse vídeo novamente" />
                            </div>
                        </div>
                    </div>
                </footer>
            </div>
        </section>
        <div class="slds-backdrop slds-backdrop_open"></div>
    </aura:if>
</aura:component> 
                        
You can do something like this;
({
})
Apex Controller