Update the dependency manager file stack when rendering blog post pages.

src/context/dependency_manager.rs

@@ -1,5 +1,7 @@
 use std::path::PathBuf;
 
+use crate::error::CustomError;
+
 pub(crate) type RefDependencyManager = std::sync::Arc<std::sync::Mutex<DependencyManager>>;
 
 #[derive(Debug)]
@@ -16,4 +18,19 @@ impl DependencyManager {
             file_stack: Vec::new(),
         }
     }
+
+    pub(crate) fn push_file<P>(&mut self, path: P) -> Result<(), CustomError>
+    where
+        P: Into<PathBuf>,
+    {
+        self.file_stack.push(path.into());
+        Ok(())
+    }
+
+    pub(crate) fn pop_file(&mut self) -> Result<(), CustomError> {
+        self.file_stack
+            .pop()
+            .expect("Popped more files off the dependency manager file stack than exist.");
+        Ok(())
+    }
 }