Add error handling and dependency injection example (#23)

src/response.rs

@@ -188,6 +188,12 @@ where
     }
 }
 
+impl<T> From<T> for Html<T> {
+    fn from(inner: T) -> Self {
+        Self(inner)
+    }
+}
+
 /// A JSON response.
 ///
 /// Can be created from any type that implements [`serde::Serialize`].
@@ -238,3 +244,9 @@ where
         res
     }
 }
+
+impl<T> From<T> for Json<T> {
+    fn from(inner: T) -> Self {
+        Self(inner)
+    }
+}