Relax census geoid constraint (#382)

* Relax census geoid constraint

* Add unique index on census values

* Additional census schema additions

schema/postgres/migrations/20241022000157_census_geoid.up.pgsql

@@ -0,0 +1,15 @@
+BEGIN;
+
+ALTER TABLE tl_census_values DROP COLUMN geography_id;
+ALTER TABLE tl_census_values ADD COLUMN geoid TEXT NOT NULL;
+CREATE INDEX ON tl_census_values(geoid);
+CREATE UNIQUE INDEX ON tl_census_values(geoid, table_id);
+
+ALTER TABLE tl_census_values ADD COLUMN source_id bigint not null REFERENCES tl_census_sources(id);
+CREATE INDEX ON tl_census_values(source_id);
+
+ALTER TABLE tl_census_tables ADD COLUMN table_details text;
+
+ALTER TABLE tl_census_fields ADD COLUMN column_order double precision;
+
+COMMIT;