Update MIGRATIONS.md

Author: falconexe

MIGRATIONS.md

@@ -80,10 +80,11 @@ Typical steps:
 
    - In the **"proof"** field you can enter "spacebar" key.
 
-2. Then Submit the extrinsic:
+2. Then Submit the extrinsic using the same collator account as origin:
 
    ```
    collatorSelection.registerAsCandidate()
    ```
+   **Requirement:** The collator account needs **> 32 XRT** in free balance to register as a candidate.
 
 3. Wait for the session change to complete. After that, your node should appear in the candidate list and begin authoring blocks.