docs(instances): update instances list

add a new insatnce

fix https://github.com/zyachel/libremdb/issues/8

README.md

@@ -37,6 +37,7 @@ Inspired by projects like [teddit](https://codeberg.org/teddit/teddit), [nitter]
 | https://libremdb.herokuapp.com   | United States | Official; Hosted on Heroku                                |
 | https://libremdb.pussthecat.org  | Germany       | Operated by [PussTheCat.org](https://pussthecat.org/)     |
 | https://libremdbeu.herokuapp.com | Europe        | Operated by [toyboatcash](https://github.com/toyboatcash) |
+| https://lmdb.tokhmi.xyz/         | U.S.          | Operated by [Tokhmi](https://tokhmi.xyz)                  |
 
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