add table for user roles

db/statusnet.sql

@@ -557,3 +557,13 @@ create table config (
     constraint primary key (section, setting)
 
 ) ENGINE=InnoDB CHARACTER SET utf8 COLLATE utf8_bin;
+
+create table user_role (
+
+    user_id integer not null comment 'user having the role' references user (id),
+    role    varchar(32) not null comment 'string representing the role',
+    created datetime not null comment 'date the role was granted',
+
+    constraint primary key (user_id, role)
+
+) ENGINE=InnoDB CHARACTER SET utf8 COLLATE utf8_bin;