limits ID cards to one account

code/game/machinery/computer/card.dm

@@ -255,7 +255,7 @@ GLOBAL_VAR_INIT(time_last_changed_position, 0)
 	else if(mode == 4)
 		dat += {"<a href='?src=[REF(src)];choice=return'>Return</a>
 		<table><tr><td style='width:25%'><b>Bank Accounts</b></td><td style='width:25%'></td></tr>"}
-		for(var/datum/bank_account/account in SSeconomy.bank_accounts)
+		for(var/datum/bank_account/account as anything in SSeconomy.bank_accounts)
 			dat += {"<td>[account.account_holder] - [account.account_id]"}
 			dat += "<a href='?src=[REF(src)];choice=bankassign;assign_bank=[REF(account)]'>Assign to ID</a></td>"
 			dat += "</td><tr>"

code/game/objects/items/cards_ids.dm

@@ -171,10 +171,10 @@
 	var/registered_name = null // The name registered_name on the card
 	var/assignment = null
 	var/access_txt // mapping aid
-	var/datum/bank_account/registered_account
 	var/uses_overlays = TRUE
 	var/uses_assignment = TRUE
 	var/icon/cached_flat_icon
+	var/datum/bank_account/registered_account
 
 /obj/item/card/id/Initialize(mapload)
 	. = ..()
@@ -200,6 +200,9 @@
 	if(mining_points)
 		. += "There's [mining_points] mining equipment redemption point\s loaded onto this card."
 
+/obj/item/card/id/proc/create_bank_account(owner, job_assignment)
+	registered_account = new/datum/bank_account(owner, job_assignment, src)
+
 /obj/item/card/id/GetAccess()
 	return access
 
@@ -643,7 +646,7 @@
 	icon_state = "retrosci"
 	uses_overlays = FALSE
 	uses_assignment = FALSE
-	
+
 /obj/item/card/id/away/snowdin/med
 	name = "Arctic Station Doctor's ID card"
 	desc = "A faded Arctic Station ID card. You can make out the rank \"Doctor\"."