mod_http_muc_log: Correctly handle changed or retracted reactions Since per XEP-0444 each reaction should overwrite all previous reactions on a particular message from a particular occupant. Previously repeated reactions would be counted again and retractions were not handled.

This module lets you block connections to any remote servers not on a
whitelist.

``` {.lua}
modules_enabled = {
    -- other modules --
    "s2s_whitelist",

}
s2s_whitelist = {
    "example.org",
}
```