add invite system schema changes

config/schema.xml

@@ -9,6 +9,8 @@
         <column name="username" type="varchar" size="64" />
         <column name="password" type="varchar" size="64" />
         <column name="superuser" type="boolean" default="false" />
+        <column name="max_invites" type="integer" default="0" />
+        <column name="used_invites" type="integer" default="0" />
 
         <unique>
             <unique-column name="username" />
@@ -46,6 +48,11 @@
     <table name="Invite">
         <column name="id" type="integer" primaryKey="true" autoIncrement="true" />
         <column name="invite" type="varchar" size="64" />
+        <column name="owner" type="integer" />
+
+        <foreign-key foreignTable="User">
+            <reference local="owner" foreign="id" />
+        </foreign-key>
     </table>
 
     <table name="Server">