Refactor RateLimiter so that if Redis is not running, everything still runs normally (minus the rate limiting protection). My assumption that creating a Redis connection would throw an exception if Redis wasn't running was wrong. The exceptions actually occur when you issue a command. This is for #224.

"""
This file contains the admin definitions for the donations application.
"""
from django.contrib import admin
from donations.models import Donation

class DonationAdmin(admin.ModelAdmin):
    raw_id_fields = ('user', )

admin.site.register(Donation, DonationAdmin)