adds basic pgsql file

src/pg/sql/21_gwr.sql

@@ -0,0 +1,11 @@
+CREATE OR REPLACE FUNCTION
+CDB_GWR(subquery text, dep_var text, ind_vars text[],
+       fixed boolean default False, kernel text default 'bisquare')
+RETURNS table(v1 numeric, v2 numeric, v3 numeric, v4 numeric, v5 numeric, v6 numeric, rowid bigint)
+AS $$
+
+from crankshaft.regression import gwr
+
+return gwr(subquery, dep_var, ind_vars, fixed, kernel)
+
+$$ LANGUAGE plpythonu;