message: Update SQL Plugin README.md
diff: -# SQL Plugin Basic Guide
  +# SQL Plugin Reference
  -## Environment Variable Configuration
  -
  -Configuration of NWNX plugins are controlled by environment variables exported prior to starting the ``nwserver`` binary. Typical usage would be in the script used to start the server
  -
  -## Plugin Loading
  -
  -Inclusion or exclusion of the plugin at server startup time is contolled by the environment variable ``NWNX_SQL_SKIP``.
  -
  -Setting this to ``Y`` will cause the plugin to _BE SKIPPED_ at startup.
  -Setting this to ``N`` will load the plugin for use.
  -
  -__Example__
  -```
  -# Load the sql plugin at startup
  -export NWNX_SQL_SKIP=N
  -```
  +## Environment Variables
  ### NWNX_SQL_TYPE
  Controls the target database type used at runtime.
  -Possible values:
  +Possible values (case insensitive):
  * ``MYSQL``
  * ``POSTGRESQL``
  