diff --git a/backend/src/endpoint/contest.rs b/backend/src/endpoint/contest.rs
index 6e855af9..143546d3 100644
--- a/backend/src/endpoint/contest.rs
+++ b/backend/src/endpoint/contest.rs
@@ -106,7 +106,7 @@ impl ContestSet for Arc<Server> {
             }
             list_request::Request::Pager(old) => {
                 reverse = old.reverse;
-                <Pager<Entity> as NoParentPager<Entity>>::from_raw(old.session, &self)?
+                <Pager<Entity> as NoParentPager<Entity>>::from_raw(old.session, self)?
             }
         };
 
@@ -117,7 +117,7 @@ impl ContestSet for Arc<Server> {
             .map(|x| x.into())
             .collect();
 
-        let next_session = pager.into_raw(&self);
+        let next_session = pager.into_raw(self);
 
         Ok(Response::new(ListContestResponse { list, next_session }))
     }
@@ -133,7 +133,7 @@ impl ContestSet for Arc<Server> {
             text_search_request::Request::Text(create) => Pager::text_search(create),
             text_search_request::Request::Pager(old) => {
                 reverse = old.reverse;
-                <Pager<_> as NoParentPager<Entity>>::from_raw(old.session, &self)?
+                <Pager<_> as NoParentPager<Entity>>::from_raw(old.session, self)?
             }
         };
 
@@ -144,7 +144,7 @@ impl ContestSet for Arc<Server> {
             .map(|x| x.into())
             .collect();
 
-        let next_session = pager.into_raw(&self);
+        let next_session = pager.into_raw(self);
 
         Ok(Response::new(ListContestResponse { list, next_session }))
     }
diff --git a/backend/src/endpoint/education.rs b/backend/src/endpoint/education.rs
index 2c759a0d..8bfc8c7a 100644
--- a/backend/src/endpoint/education.rs
+++ b/backend/src/endpoint/education.rs
@@ -236,7 +236,7 @@ impl EducationSet for Arc<Server> {
                 reverse = old.reverse;
                 <Pager<Entity> as HasParentPager<problem::Entity, Entity>>::from_raw(
                     old.session,
-                    &self,
+                    self,
                 )?
             }
         };
@@ -248,7 +248,7 @@ impl EducationSet for Arc<Server> {
             .map(|x| x.into())
             .collect();
 
-        let next_session = pager.into_raw(&self);
+        let next_session = pager.into_raw(self);
 
         Ok(Response::new(ListEducationResponse { list, next_session }))
     }
diff --git a/backend/src/endpoint/problem.rs b/backend/src/endpoint/problem.rs
index f8bd8966..6ad0dbd7 100644
--- a/backend/src/endpoint/problem.rs
+++ b/backend/src/endpoint/problem.rs
@@ -114,7 +114,7 @@ impl ProblemSet for Arc<Server> {
                 reverse = old.reverse;
                 <Pager<Entity> as HasParentPager<contest::Entity, Entity>>::from_raw(
                     old.session,
-                    &self,
+                    self,
                 )?
             }
         };
@@ -126,7 +126,7 @@ impl ProblemSet for Arc<Server> {
             .map(|x| x.into())
             .collect();
 
-        let next_session = pager.into_raw(&self);
+        let next_session = pager.into_raw(self);
 
         Ok(Response::new(ListProblemResponse { list, next_session }))
     }
@@ -145,7 +145,7 @@ impl ProblemSet for Arc<Server> {
             }
             text_search_request::Request::Pager(old) => {
                 reverse = old.reverse;
-                <Pager<_> as HasParentPager<contest::Entity, Entity>>::from_raw(old.session, &self)?
+                <Pager<_> as HasParentPager<contest::Entity, Entity>>::from_raw(old.session, self)?
             }
         };
 
@@ -156,7 +156,7 @@ impl ProblemSet for Arc<Server> {
             .map(|x| x.into())
             .collect();
 
-        let next_session = pager.into_raw(&self);
+        let next_session = pager.into_raw(self);
 
         Ok(Response::new(ListProblemResponse { list, next_session }))
     }
@@ -414,7 +414,7 @@ impl ProblemSet for Arc<Server> {
                 reverse = old.reverse;
                 <Pager<Entity> as HasParentPager<contest::Entity, Entity>>::from_raw(
                     old.session,
-                    &self,
+                    self,
                 )?
             }
         };
@@ -426,7 +426,7 @@ impl ProblemSet for Arc<Server> {
             .map(|x| x.into())
             .collect();
 
-        let next_session = pager.into_raw(&self);
+        let next_session = pager.into_raw(self);
 
         Ok(Response::new(ListProblemResponse { list, next_session }))
     }
diff --git a/backend/src/endpoint/submit.rs b/backend/src/endpoint/submit.rs
index 5f119b99..ca2c2314 100644
--- a/backend/src/endpoint/submit.rs
+++ b/backend/src/endpoint/submit.rs
@@ -77,7 +77,7 @@ impl SubmitSet for Arc<Server> {
                 reverse = old.reverse;
                 <Pager<Entity> as HasParentPager<problem::Entity, Entity>>::from_raw(
                     old.session,
-                    &self,
+                    self,
                 )?
             }
         };
@@ -89,7 +89,7 @@ impl SubmitSet for Arc<Server> {
             .map(|x| x.into())
             .collect();
 
-        let next_session = pager.into_raw(&self);
+        let next_session = pager.into_raw(self);
 
         Ok(Response::new(ListSubmitResponse { list, next_session }))
     }
@@ -111,7 +111,7 @@ impl SubmitSet for Arc<Server> {
                 reverse = old.reverse;
                 <Pager<Entity> as HasParentPager<problem::Entity, Entity>>::from_raw(
                     old.session,
-                    &self,
+                    self,
                 )?
             }
         };
@@ -123,7 +123,7 @@ impl SubmitSet for Arc<Server> {
             .map(|x| x.into())
             .collect();
 
-        let next_session = pager.into_raw(&self);
+        let next_session = pager.into_raw(self);
 
         Ok(Response::new(ListSubmitResponse { list, next_session }))
     }
diff --git a/backend/src/endpoint/testcase.rs b/backend/src/endpoint/testcase.rs
index cacd5c0a..4e1acbe6 100644
--- a/backend/src/endpoint/testcase.rs
+++ b/backend/src/endpoint/testcase.rs
@@ -97,7 +97,7 @@ impl TestcaseSet for Arc<Server> {
                 reverse = old.reverse;
                 <Pager<Entity> as HasParentPager<problem::Entity, Entity>>::from_raw(
                     old.session,
-                    &self,
+                    self,
                 )?
             }
         };
@@ -109,7 +109,7 @@ impl TestcaseSet for Arc<Server> {
             .map(|x| x.into())
             .collect();
 
-        let next_session = pager.into_raw(&self);
+        let next_session = pager.into_raw(self);
 
         Ok(Response::new(ListTestcaseResponse { list, next_session }))
     }
@@ -298,7 +298,7 @@ impl TestcaseSet for Arc<Server> {
                 reverse = old.reverse;
                 <Pager<Entity> as HasParentPager<problem::Entity, Entity>>::from_raw(
                     old.session,
-                    &self,
+                    self,
                 )?
             }
         };
@@ -310,7 +310,7 @@ impl TestcaseSet for Arc<Server> {
             .map(|x| x.into())
             .collect();
 
-        let next_session = pager.into_raw(&self);
+        let next_session = pager.into_raw(self);
 
         Ok(Response::new(ListTestcaseResponse { list, next_session }))
     }
diff --git a/backend/src/endpoint/user.rs b/backend/src/endpoint/user.rs
index 7bd5edb7..e99e8008 100644
--- a/backend/src/endpoint/user.rs
+++ b/backend/src/endpoint/user.rs
@@ -105,7 +105,7 @@ impl UserSet for Arc<Server> {
             }
             list_request::Request::Pager(old) => {
                 reverse = old.reverse;
-                <Pager<Entity> as NoParentPager<Entity>>::from_raw(old.session, &self)?
+                <Pager<Entity> as NoParentPager<Entity>>::from_raw(old.session, self)?
             }
         };
 
@@ -116,7 +116,7 @@ impl UserSet for Arc<Server> {
             .map(|x| x.into())
             .collect();
 
-        let next_session = pager.into_raw(&self);
+        let next_session = pager.into_raw(self);
 
         Ok(Response::new(ListUserResponse { list, next_session }))
     }
@@ -132,7 +132,7 @@ impl UserSet for Arc<Server> {
             text_search_request::Request::Text(create) => Pager::text_search(create),
             text_search_request::Request::Pager(old) => {
                 reverse = old.reverse;
-                <Pager<_> as NoParentPager<Entity>>::from_raw(old.session, &self)?
+                <Pager<_> as NoParentPager<Entity>>::from_raw(old.session, self)?
             }
         };
 
@@ -143,7 +143,7 @@ impl UserSet for Arc<Server> {
             .map(|x| x.into())
             .collect();
 
-        let next_session = pager.into_raw(&self);
+        let next_session = pager.into_raw(self);
 
         Ok(Response::new(ListUserResponse { list, next_session }))
     }
diff --git a/backend/src/endpoint/util/pagination.rs b/backend/src/endpoint/util/pagination.rs
index c1298a1c..e0c7d2b8 100644
--- a/backend/src/endpoint/util/pagination.rs
+++ b/backend/src/endpoint/util/pagination.rs
@@ -136,7 +136,7 @@ where
                 SearchDep::Parent(x) => RawSearchDep::Parent(x),
             },
         };
-        let byte = server.crypto.encode(&raw);
+        let byte = server.crypto.encode(raw);
 
         base64::Engine::encode(
             &base64::engine::general_purpose::STANDARD_NO_PAD,
@@ -273,7 +273,7 @@ where
                 SearchDep::Parent(x) => RawSearchDep::Parent(x),
             },
         };
-        let byte = server.crypto.encode(&raw);
+        let byte = server.crypto.encode(raw);
 
         base64::Engine::encode(
             &base64::engine::general_purpose::STANDARD_NO_PAD,
diff --git a/backend/src/grpc.rs b/backend/src/grpc.rs
index 17e8c2bd..a0c91c71 100644
--- a/backend/src/grpc.rs
+++ b/backend/src/grpc.rs
@@ -36,7 +36,7 @@ impl Hash for judger::LangInfo {
 
 impl PartialOrd for judger::LangInfo {
     fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-        self.lang_uid.partial_cmp(&other.lang_uid)
+        Some(self.lang_uid.cmp(&other.lang_uid))
     }
 }
 
diff --git a/docker/quickstart/backend.toml b/docker/quickstart/backend.toml
index 7b54623b..c87c212b 100644
--- a/docker/quickstart/backend.toml
+++ b/docker/quickstart/backend.toml
@@ -13,3 +13,7 @@ type = "static"
 trust_x_forwarded_for = true
 public_pem = "../cert/cert.pem"
 private_pem = "../cert/key.pem"
+
+[imgur]
+client_id = "fffffffffffffff"
+client_secret = "ffffffffffffffffffffffffffffffffffffffff"