Update register_user.md

pages/features-documentation/register_user.md

@@ -17,7 +17,7 @@ Organization administrators can use their registered credentials and add individ
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-    <td>1. You are logged in <br>2. You are currently on <strong>Profile</strong> page. You want to upload users <br>3. You have clicked on <b>Upload Users</b> 
+    <td>1. You are logged in <br>2. You are currently on <strong>Profile</strong> page. You want to upload users <br>3. You have clicked on <b>Upload Users</b> <br><b>Note</b>: Ensure that the administrator of your organization has assigned user roles on the portal. For details on how to assign user roles, refer <a href="http://www.sunbird.org/features-documentation/admin_assigning_users" target="_blank">Assigning User Roles</a>
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       <td><img src="pages/features-documentation/images/upldusr_prereqsite.png"></td>
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