Parsing Fix: Add H2 Paragraph type

The post id 34dead42a28 contained a new paragraph type: H2. Previously
the only known header types were H3 and H4. In this case, the paragraph
doesn't actually get rendered because it's the page title which is
removed from the page nodes (see commits 6baba803 and then fba87c10).
However, it somehow an author is able to get an H2 paragraph into the
page, it will display as an <h1> just as H3 displays as <h2> and H4
displays as <h3>.

spec/classes/paragraph_converter_spec.cr

@@ -190,6 +190,14 @@ describe ParagraphConverter do
   it "converts all the tags" do
     paragraphs = Array(PostResponse::Paragraph).from_json <<-JSON
       [
+        {
+          "text": "text",
+          "type": "H2",
+          "markups": [],
+          "iframe": null,
+          "layout": null,
+          "metadata": null
+        },
         {
           "text": "text",
           "type": "H3",
@@ -303,6 +311,7 @@ describe ParagraphConverter do
       ]
     JSON
     expected = [
+      Heading1.new([Text.new("text")] of Child),
       Heading2.new([Text.new("text")] of Child),
       Heading3.new([Text.new("text")] of Child),
       Paragraph.new([Text.new("text")] of Child),

spec/components/page_content_spec.cr

@@ -162,6 +162,23 @@ describe PageContent do
     HTML
   end
 
+  it "renders an H2" do
+    page = Page.new(
+      title: "Title",
+      author: user_anchor_factory,
+      created_at: Time.local,
+      nodes: [
+        Heading1.new(children: [
+          Text.new(content: "Title!"),
+        ] of Child),
+      ] of Child
+    )
+
+    html = PageContent.new(page: page).render_to_string
+
+    html.should eq %(<h1>Title!</h1>)
+  end
+
   it "renders an H3" do
     page = Page.new(
       title: "Title",

src/classes/paragraph_converter.cr

@@ -10,6 +10,10 @@ class ParagraphConverter
         paragraph = paragraphs.shift
         children = MarkupConverter.convert(paragraph.text, paragraph.markups)
         node = BlockQuote.new(children: children)
+      when PostResponse::ParagraphType::H2
+        paragraph = paragraphs.shift
+        children = MarkupConverter.convert(paragraph.text, paragraph.markups)
+        node = Heading1.new(children: children)
       when PostResponse::ParagraphType::H3
         paragraph = paragraphs.shift
         children = MarkupConverter.convert(paragraph.text, paragraph.markups)

src/components/page_content.cr

@@ -81,6 +81,10 @@ class PageContent < BaseComponent
     script src: child.src
   end
 
+  def render_child(node : Heading1)
+    h1 { render_children(node.children) }
+  end
+
   def render_child(node : Heading2)
     h2 { render_children(node.children) }
   end

src/models/nodes.cr

@@ -40,6 +40,9 @@ module Nodes
   class FigureCaption < Container
   end
 
+  class Heading1 < Container
+  end
+
   class Heading2 < Container
   end
 

src/models/post_response.cr

@@ -42,6 +42,7 @@ class PostResponse
 
   enum ParagraphType
     BQ
+    H2
     H3
     H4
     IFRAME