fix typo

README.md

@@ -61,7 +61,7 @@ By default Janitor output to STDOUT for piping.
 
 Trimming allows much smaller database dumps by reducing the data exported. It does so by only keeping every fourth row,
 and allows you to completely scrub tables (e.g caches) to further reduce the size. Is as non destructive as possible,
-renaming the original table beforehand (and cleaning up afterwads).
+renaming the original table beforehand (and cleaning up afterwards).
 
 ```bash
 ./database-janitor --host=localhost:8787 --username=real --trim=true real | gzip -c > output/real_test.sql.gz