[x] Clicking "Update" on the group's detail page navigates the user to the update group form which looks like the same as the create a new group form, but pre-populated with the values stored in the database for that group, the title changed to "Update your Group", and with a submit button text of "Update Group". Image URL input on the update group form is optional for MVP.
[x] Navigating to the update group form as a user who is logged-in but does not own the group or as a user who is not logged-in will not show the update group form and automatically navigate the user to the landing page.
[x] When the update form submission is successful, the user is navigated to the updated group's details page.
[x] The updated group's detail page should display the updated information. No refresh should be necessary.