Another major Pinry model rewrite

Generate thumbnail and standard image on request, and use
http://github.com/mirumee/django-images for generating them. Also,
remove the CreatePin page as pin creation is going to be done
in JavaScript. Create UploadImage view for uploading images from
computer.

pinry/pins/models.py

@@ -1,89 +1,21 @@
-import hashlib
-
 from django.db import models
 
+from django_images.models import Image
 from taggit.managers import TaggableManager
 
 from ..core.models import User
-from .managers import OriginalImageManager
-from .managers import StandardImageManager
-from .managers import ThumbnailManager
-
-
-def hashed_upload_to(prefix, instance, filename):
-    md5 = hashlib.md5()
-    for chunk in instance.image.chunks():
-        md5.update(chunk)
-    file_hash = md5.hexdigest()
-    arguments = {
-        'prefix': prefix,
-        'first': file_hash[0],
-        'second': file_hash[1],
-        'hash': file_hash,
-        'filename': filename
-    }
-    return "{prefix}/{first}/{second}/{hash}/{filename}".format(**arguments)
-
-
-def original_upload_to(instance, filename):
-    return hashed_upload_to('image/original/by-md5', instance, filename)
-
-
-def thumbnail_upload_to(instance, filename):
-    return hashed_upload_to('image/thumbnail/by-md5', instance, filename)
-
-
-def standard_upload_to(instance, filename):
-    return hashed_upload_to('image/standard/by-md5', instance, filename)
-
-
-class Image(models.Model):
-    height = models.PositiveIntegerField(default=0, editable=False)
-    width = models.PositiveIntegerField(default=0, editable=False)
-
-    class Meta:
-        abstract = True
-
-
-class OriginalImage(Image):
-    image = models.ImageField(upload_to=original_upload_to,
-                              height_field='height', width_field='width', max_length=255)
-    objects = OriginalImageManager()
-
-
-class StandardImage(Image):
-    original = models.ForeignKey(OriginalImage, related_name='standard')
-    image = models.ImageField(upload_to=standard_upload_to,
-                              height_field='height', width_field='width', max_length=255)
-    objects = StandardImageManager()
-
-
-class Thumbnail(Image):
-    original = models.ForeignKey(OriginalImage, related_name='thumbnail')
-    image = models.ImageField(upload_to=thumbnail_upload_to,
-                              height_field='height', width_field='width', max_length=255)
-    objects = ThumbnailManager()
 
 
 class Pin(models.Model):
     submitter = models.ForeignKey(User)
     url = models.TextField(blank=True, null=True)
     description = models.TextField(blank=True, null=True)
-    original = models.ForeignKey(OriginalImage, related_name='pin')
-    standard = models.ForeignKey(StandardImage, related_name='pin')
-    thumbnail = models.ForeignKey(Thumbnail, related_name='pin')
+    image = models.ForeignKey(Image, related_name='pin')
     published = models.DateTimeField(auto_now_add=True)
     tags = TaggableManager()
 
     def __unicode__(self):
         return self.url
 
-    def save(self, *args, **kwargs):
-        if not self.pk:
-            self.original = OriginalImage.objects.create_for_url(self.url)
-            self.standard = StandardImage.objects.get_or_create_for(self.original)
-            self.thumbnail = Thumbnail.objects.get_or_create_for(self.original)
-        super(Pin, self).save(*args, **kwargs)
-
     class Meta:
         ordering = ['-id']