prompt: You will be provided with a partial code base and an issue statement explaining a problem to resolve.
  <issue>
  Add Categories to the Sitemap
  Sitemap consists of Products only, we should expand it to include categories as well.
  
  </issue>
  <code>
  [start of saleor/core/sitemaps.py]
  1 from __future__ import unicode_literals
  2 
  3 from django.contrib.sitemaps import Sitemap
  4 
  5 from ..product.models import Product
  6 
  7 
  8 class ProductSitemap(Sitemap):
  9 
  10     def items(self):
  11         return Product.objects.only('id', 'name').order_by('-id')
  12 
  13 
  14 sitemaps = {'products': ProductSitemap}
  15
  [end of saleor/core/sitemaps.py]
  </code>
  
  I need you to solve this issue by generating a single patch file that I can apply directly to this repository using git apply. Please respond with a single patch file in the following format.
  <patch>
  diff --git a/file.py b/file.py
  --- a/file.py
  +++ b/file.py
  @@ -1,27 +1,35 @@
   def euclidean(a, b):
  -    while b:
  -        a, b = b, a % b
  -    return a
  +    if b == 0:
  +        return a
  +    return euclidean(b, a % b)
   
   
   def bresenham(x0, y0, x1, y1):
       points = []
       dx = abs(x1 - x0)
       dy = abs(y1 - y0)
  -    sx = 1 if x0 < x1 else -1
  -    sy = 1 if y0 < y1 else -1
  -    err = dx - dy
  +    x, y = x0, y0
  +    sx = -1 if x0 > x1 else 1
  +    sy = -1 if y0 > y1 else 1
   
  -    while True:
  -        points.append((x0, y0))
  -        if x0 == x1 and y0 == y1:
  -            break
  -        e2 = 2 * err
  -        if e2 > -dy:
  -            err -= dy
  -            x0 += sx
  -        if e2 < dx:
  -            err += dx
  -            y0 += sy
  +    if dx > dy:
  +        err = dx / 2.0
  +        while x != x1:
  +            points.append((x, y))
  +            err -= dy
  +            if err < 0:
  +                y += sy
  +                err += dx
  +            x += sx
  +    else:
  +        err = dy / 2.0
  +        while y != y1:
  +            points.append((x, y))
  +            err -= dx
  +            if err < 0:
  +                x += sx
  +                err += dy
  +            y += sy
  +
  +    points.append((x, y))
       return points
  
  </patch>
golden_diff: diff --git a/saleor/core/sitemaps.py b/saleor/core/sitemaps.py
  --- a/saleor/core/sitemaps.py
  +++ b/saleor/core/sitemaps.py
  @@ -2,7 +2,7 @@
   
   from django.contrib.sitemaps import Sitemap
   
  -from ..product.models import Product
  +from ..product.models import Category, Product
   
   
   class ProductSitemap(Sitemap):
  @@ -11,4 +11,13 @@
           return Product.objects.only('id', 'name').order_by('-id')
   
   
  -sitemaps = {'products': ProductSitemap}
  +class CategorySitemap(Sitemap):
  +
  +    def items(self):
  +        categories = Category.objects.all().order_by('id')
  +        return categories.only('id', 'name', 'slug')
  +
  +sitemaps = {
  +    'categories': CategorySitemap,
  +    'products': ProductSitemap
  +}
  
verification_info: {"golden_diff": "diff --git a/saleor/core/sitemaps.py b/saleor/core/sitemaps.py\n--- a/saleor/core/sitemaps.py\n+++ b/saleor/core/sitemaps.py\n@@ -2,7 +2,7 @@\n \n from django.contrib.sitemaps import Sitemap\n \n-from ..product.models import Product\n+from ..product.models import Category, Product\n \n \n class ProductSitemap(Sitemap):\n@@ -11,4 +11,13 @@\n         return Product.objects.only('id', 'name').order_by('-id')\n \n \n-sitemaps = {'products': ProductSitemap}\n+class CategorySitemap(Sitemap):\n+\n+    def items(self):\n+        categories = Category.objects.all().order_by('id')\n+        return categories.only('id', 'name', 'slug')\n+\n+sitemaps = {\n+    'categories': CategorySitemap,\n+    'products': ProductSitemap\n+}\n", "issue": "Add Categories to the Sitemap\nSitemap consists of Products only, we should expand it to include categories as well.\n", "before_files": [{"content": "from __future__ import unicode_literals\n\nfrom django.contrib.sitemaps import Sitemap\n\nfrom ..product.models import Product\n\n\nclass ProductSitemap(Sitemap):\n\n    def items(self):\n        return Product.objects.only('id', 'name').order_by('-id')\n\n\nsitemaps = {'products': ProductSitemap}\n", "path": "saleor/core/sitemaps.py"}]}