Add the skeletons for the elements.

src/context/horizontal_rule.rs

@@ -0,0 +1,23 @@
+use std::path::Path;
+
+use serde::Serialize;
+
+use crate::config::Config;
+use crate::error::CustomError;
+use crate::intermediate::IHorizontalRule;
+
+#[derive(Debug, Serialize)]
+#[serde(tag = "type")]
+#[serde(rename = "horizontal_rule")]
+pub(crate) struct RenderHorizontalRule {}
+
+impl RenderHorizontalRule {
+    pub(crate) fn new<D: AsRef<Path>, F: AsRef<Path>>(
+        config: &Config,
+        output_directory: D,
+        output_file: F,
+        original: &IHorizontalRule,
+    ) -> Result<RenderHorizontalRule, CustomError> {
+        Ok(RenderHorizontalRule {})
+    }
+}