ASP.NET MVC: Save multiple values on autocomplete

I have a mysql database with the tables "deliverables", "tags" and "deliverables_has_tags". I want to link tags to a deliverable.

This is what I do in my javascript file:

<script type="text/javascript" language="javascript">
    $(function () {
        var object = {};
        $.ajax({
            type: "GET",
            url: "/Deliverable/Tags",
            dataType: "json",
            success: function (data) {
                object.tags = data;
            }
        });

        function split(val) {
            return val.split(/,\s*/);
        }
        function extractLast(term) {
            return split(term).pop();
        }
        $("#tags")
        // don't navigate away from the field on tab when selecting an item
            .bind("keydown", function (event) {
                if (event.keyCode === $.ui.keyCode.TAB &&
                $(this).data("ui-autocomplete").menu.active) {
                    event.preventDefault();
                }
            })

.autocomplete({
    minLength: 0,
    source: function (request, response) {
        // delegate back to autocomplete, but extract the last term
        response($.ui.autocomplete.filter(
object.tags, extractLast(request.term)));
    },
    focus: function () {
        // prevent value inserted on focus
        return false;
    },
    select: function (event, ui) {
        var terms = split(this.value);
        // remove the current input
        terms.pop();
        // add the selected item
        terms.push(ui.item.value);
        // add placeholder to get the comma-and-space at the end
        terms.push("");
        this.value = terms.join(", ");

        return false;
    }
});
    });
</script>

I can add multiple tags in my textbox.

But now I want to save this in my repository. In my Action method in controller:

repository.AddDeliverable(model.Title, model.Description, model.UsernameID, data, datatwo, model.VideoUrl, model.AfstudeerrichtingID, model.ProjectID);

Tags action:

public JsonResult Tags()
{
    var data = (repository.GetTags()).ToArray();

    return Json(data, JsonRequestBehavior.AllowGet);
}

In my repository:

public IQueryable<string> GetTags()
{
    return from tag in entities.tags
           orderby tag.tag_name
           select tag.tag_name;
}

I have no clue how to save this in my database.
Can anybody help me?