Ability to add / edit food resource types

+ Created `ColoredPin` and `FoodResourceType` models.
+ Created “Add New Food Resource Type” and “Manage Food Resource Types” pages so that admins can add and edit food resource types.
+ Created “Add New / Edit Food Resource Type” form. 
+ Updated `all_resources.csv` with different food resource type enums.
+ Replaced hard-coded static file links with `url_for` function calls.
I think 200 sounds good.