Allow editing trip metadata

[tammy]

What we should have:

• On creating a trip, you can upload a picture.
• On a trip, there should be an option to edit the picture.

[justinli610]

Adding a picture is now implemented. This task should be changed to something along the lines of "allow editing trip metadata"

[justinli610]

On another note, it would be nice if we supported uploaded images (using URLs right now), but that requires file storage to be implemented.

[tammy]

What metadata is there other than pictures right now? I can only think of changing owners, and we already have title changing implemented.

[justinli610]

Description, which is unused. Changing owners is probably not necessary.