message: SQL: update documentation readme
diff: @@ -50,3 +50,13 @@ __Example__
  ```
  export NWNX_SQL_PASSWORD=lathander_rulez
  ```
  +
  +### NWNX_SQL_DATABASE
  +
  +The database to connect to.
  +
  +__Example__
  +
  +```
  +export NWNX_SQL_DATABASE=mymodulename
  +```
  