Get and store steam username and display it on the homepage

backend/src/schema.rs

@@ -1,14 +1,21 @@
 diesel::table! {
     sessions (id) {
         id -> Array<BigInt>,
-        data -> Jsonb,
+        steamid -> Nullable<Text>,
         expiry_date -> Text,
     }
 }
 
 diesel::table! {
-    demos (steam_id) {
+    demos (steam_id, demo_id) {
         steam_id -> BigInt,
         demo_id -> BigInt
     }
 }
+
+diesel::table! {
+    users (steamid) {
+        steamid -> Text,
+        name -> Text
+    }
+}