fix(db): update user name field conditionally

prevents name from flip-flopping between auth providers if it's
different on each platform. The name will not change from the one that
is used in the first login, even if a new provider is used with the same
email address and a different name.

data/data.go

@@ -69,8 +69,17 @@ func createUser(db *sql.DB, user *User) error {
 }
 
 func updateUser(db *sql.DB, user *User) error {
-	_, err := db.Exec(
-		"UPDATE users SET name = ?, discord_id = ?, github_id = ? WHERE email = ?",
+	_, err := db.Exec(`
+        UPDATE users
+        SET
+            name = CASE
+                WHEN name IS NULL THEN ?
+                ELSE name
+            END,
+            discord_id = ?,
+            github_id = ?
+        WHERE email = ?
+    `,
 		user.Name,
 		user.DiscordID,
 		user.GithubID,