add examples for custom converters

closes #46

README.rst

@@ -100,6 +100,29 @@ Options may be specified as kwargs to the ``markdownify`` function, or as a
 nested ``Options`` class in ``MarkdownConverter`` subclasses.
 
 
+Creating Custom Converters
+=========================
+
+If you have a special usecase that calls for a special conversion, you can
+always inherit from ``MarkdownConverter`` and override the method you want to
+change:
+
+.. code:: python
+
+    from markdownify import MarkdownConverter
+
+    class ImageBlockConverter(MarkdownConverter):
+        """
+        Create a custom MarkdownConverter that adds two newlines after an image
+        """
+        def convert_img(self, el, text, convert_as_inline):
+            return super().convert_img(el, text, convert_as_inline) + '\n\n'
+
+    # Create shorthand method for conversion
+    def md(html, **options):
+        return ImageBlockConverter(**options).convert(html)
+
+
 Development
 ===========
 

tests/test_conversions.py

@@ -131,8 +131,6 @@ def test_hn_nested_simple_tag():
 
 
 def test_hn_nested_img():
-    assert md('<img src="/path/to/img.jpg" alt="Alt text" title="Optional title" />') == '![Alt text](/path/to/img.jpg "Optional title")'
-    assert md('<img src="/path/to/img.jpg" alt="Alt text" />') == '![Alt text](/path/to/img.jpg)'
     image_attributes_to_markdown = [
         ("", ""),
         ("alt='Alt Text'", "Alt Text"),

tests/test_custom_converter.py

@@ -0,0 +1,18 @@
+from markdownify import MarkdownConverter
+
+
+class ImageBlockConverter(MarkdownConverter):
+    """
+    Create a custom MarkdownConverter that adds two newlines after an image
+    """
+    def convert_img(self, el, text, convert_as_inline):
+        return super().convert_img(el, text, convert_as_inline) + '\n\n'
+
+
+def test_img():
+    # Create shorthand method for conversion
+    def md(html, **options):
+        return ImageBlockConverter(**options).convert(html)
+
+    assert md('<img src="/path/to/img.jpg" alt="Alt text" title="Optional title" />') == '![Alt text](/path/to/img.jpg "Optional title")\n\n'
+    assert md('<img src="/path/to/img.jpg" alt="Alt text" />') == '![Alt text](/path/to/img.jpg)\n\n'