Keep ISF in suggestion.swift

FreeAPS/Sources/Models/Suggestion.swift

@@ -16,6 +16,7 @@ struct Suggestion: JSON, Equatable {
     let temp: TempType?
     let bg: Decimal?
     let reservoir: Decimal?
+    let isf: Decimal?
     var timestamp: Date?
     var recieved: Bool?
 }
@@ -46,6 +47,7 @@ extension Suggestion {
         case reservoir
         case timestamp
         case recieved
+        case isf = "ISF"
     }
 }