Create the remaining task api methods on the server. (#3)

Create the remaining task api methods along with hurl tests for each.

Reviewed-on: #3
Co-authored-by: Drew Galbraith <drew@tiramisu.one>
Co-committed-by: Drew Galbraith <drew@tiramisu.one>

backend/src/services/mod.rs

@@ -13,6 +13,7 @@ pub enum AppError {
     InternalError(anyhow::Error),
     JsonExtractError(JsonRejection),
     PathError(PathRejection),
+    Unprocessable(String),
     NotFound,
 }
 
@@ -36,6 +37,11 @@ impl IntoResponse for AppError {
                 }),
             )
                 .into_response(),
+            Self::Unprocessable(msg) => (
+                StatusCode::UNPROCESSABLE_ENTITY,
+                Json(ErrorJson { error: msg }),
+            )
+                .into_response(),
             Self::PathError(rej) => (
                 StatusCode::BAD_REQUEST,
                 Json(ErrorJson {