minor documentation change to provider/postgis.
@@ -5,7 +5,7 @@ The PostGIS provider manages querying for tile requests against a Postgres datab
```toml
[[providers]]
name = "test_postgis" # provider name is referenced from map layers (required)
-type = "postgis" # the type of data provider. currently only supports PostGIS (required)
+type = "postgis" # the type of data provider must be "postgis" for this data provider (required)
host = "localhost" # PostGIS database host (required)
port = 5432 # PostGIS database port (required)
database = "tegola" # PostGIS database name (required)
