Update db/install.xml

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: ndrwnaguib

db/install.xml

@@ -6,7 +6,7 @@
   <TABLES>
     <TABLE NAME="onlinejudge_tasks" COMMENT="Details of tasks">
       <FIELDS>
-        <FIELD NAME="id" TYPE="int" LENGTH="20" NOTNULL="true" SEQUENCE="true"/>
+        <FIELD NAME="id" TYPE="int" LENGTH="20" NOTNULL="true" SEQUENCE="true" UNSIGNED="true"/>
         <FIELD NAME="cmid" TYPE="int" LENGTH="10" NOTNULL="true" SEQUENCE="false" COMMENT="Source coursemodule ID"/>
         <FIELD NAME="userid" TYPE="int" LENGTH="10" NOTNULL="true" SEQUENCE="false" COMMENT="Related user"/>
         <FIELD NAME="language" TYPE="char" LENGTH="255" NOTNULL="true" SEQUENCE="false" COMMENT="Programming language"/>