+create table Problems (
+ id integer primary key,
+ added datetime,
+ fen varchar,
+ uid integer,
+ vid integer,
+ instruction text,
+ solution text,
+ foreign key (uid) references Users(id),
+ foreign key (vid) references Variants(id)
+);
+
+create table News (
+ id integer primary key,
+ uid integer,
+ added datetime,
+ content text,
+ foreign key (uid) references Users(id)
+);