fix: add problem service

problem/v1/problem.proto

@@ -0,0 +1,70 @@
+syntax = "proto3";
+
+package problem.v1;
+option go_package = "/problem/v1;problemv1";
+
+import "google/protobuf/timestamp.proto";
+import "google/protobuf/empty.proto";
+
+service ProblemService {
+  rpc CreateProblem (stream CreateProblemRequest) returns (CreateProblemResponse);
+  rpc ReadProblem (ReadProblemRequest) returns (ReadProblemResponse);
+  //  rpc UpdateProblem (UpdateProblemRequest) returns (google.protobuf.Empty);
+  rpc DeleteProblem (DeleteProblemRequest) returns (google.protobuf.Empty);
+}
+
+message CreateProblemRequest {
+  message Problem {
+    string name = 1;
+    string description = 2;
+    int32 time_limit = 3;
+    int32 memory_limit = 4;
+  }
+  message Test {
+    bytes chunk = 1;
+  }
+
+  oneof msg {
+    string token = 1;
+    Problem problem = 2;
+    Test test = 3;
+  }
+}
+message CreateProblemResponse {
+  int32 id = 1;
+}
+
+message ReadProblemRequest {
+  string token = 1;
+  int32 id = 2;
+}
+message ReadProblemResponse {
+  message Problem {
+    int32 id = 1;
+    string name = 2;
+    string description = 3;
+    int32 time_limit = 4;
+    int32 memory_limit = 5;
+    google.protobuf.Timestamp created_at = 6;
+    google.protobuf.Timestamp updated_at = 7;
+  }
+  string token = 1;
+  Problem problem = 2;
+}
+
+//message UpdateProblemRequest {
+//  message Problem {
+//    int32 id = 1;
+//    optional string name = 2;
+//    optional string description = 3;
+//    optional int32 time_limit = 4;
+//    optional int32 memory_limit = 5;
+//  }
+//  string token = 1;
+//  Problem problem = 2;
+//}
+
+message DeleteProblemRequest {
+  string token = 1;
+  int32 id = 2;
+}