Fix escaping for materialized view SQL

src/invidious/users.cr

@@ -1,7 +1,7 @@
 require "crypto/bcrypt/password"
 
 # Materialized views may not be defined using bound parameters (`$1` as used elsewhere)
-MATERIALIZED_VIEW_SQL = ->(email : String) { "SELECT cv.* FROM channel_videos cv WHERE EXISTS (SELECT subscriptions FROM users u WHERE cv.ucid = ANY (u.subscriptions) AND u.email = E'#{email.gsub("'", "\\'")}') ORDER BY published DESC" }
+MATERIALIZED_VIEW_SQL = ->(email : String) { "SELECT cv.* FROM channel_videos cv WHERE EXISTS (SELECT subscriptions FROM users u WHERE cv.ucid = ANY (u.subscriptions) AND u.email = E'#{email.gsub({'\'' => "\\'", '\\' => "\\\\"})}') ORDER BY published DESC" }
 
 struct User
   module PreferencesConverter