add contracts

schema/changes-contract.sql

@@ -0,0 +1,11 @@
+
+CREATE TABLE contract_t (
+  id serial not null primary key
+  ,supplier varchar(256)     not null 
+  ,content varchar(256)     not null 
+  ,identifier varchar(256)     not null 
+  ,unique(supplier, content)
+);
+
+GRANT SELECT, INSERT, UPDATE ON contract_t TO hv2;
+GRANT SELECT, UPDATE ON contract_t_id_seq TO hv2;