feat: implement user follow/unfollow functionality and thought retrieval by user

- Added follow and unfollow endpoints for users.
- Implemented logic to retrieve thoughts by a specific user.
- Updated user error handling to include cases for already following and not following.
- Created persistence layer for follow relationships.
- Enhanced user and thought schemas to support new features.
- Added tests for follow/unfollow endpoints and thought retrieval.
- Updated frontend to display thoughts and allow posting new thoughts.

thoughts-backend/doc/src/user.rs

@@ -1,18 +1,29 @@
 use utoipa::OpenApi;
 
-use models::params::user::CreateUserParams;
-use models::schemas::user::{UserListSchema, UserSchema};
-
 use api::models::{ApiErrorResponse, ParamsErrorResponse};
 use api::routers::user::*;
+use models::params::user::CreateUserParams;
+use models::schemas::{
+    thought::{ThoughtListSchema, ThoughtSchema},
+    user::{UserListSchema, UserSchema},
+};
 
 #[derive(OpenApi)]
 #[openapi(
-    paths(users_get, users_id_get, users_post),
+    paths(
+        users_get,
+        users_id_get,
+        users_post,
+        user_thoughts_get,
+        user_follow_post,
+        user_follow_delete
+    ),
     components(schemas(
         CreateUserParams,
         UserListSchema,
         UserSchema,
+        ThoughtSchema,
+        ThoughtListSchema,
         ApiErrorResponse,
         ParamsErrorResponse,
     ))