diff --git a/backend/src/main/kotlin/uk/co/neviyn/observationdatabase/Api.kt b/backend/src/main/kotlin/uk/co/neviyn/observationdatabase/Api.kt
index d7fad27..d241678 100644
--- a/backend/src/main/kotlin/uk/co/neviyn/observationdatabase/Api.kt
+++ b/backend/src/main/kotlin/uk/co/neviyn/observationdatabase/Api.kt
@@ -54,7 +54,8 @@ data class ChartDataset(
         val backgroundColor: String,
         val borderColor: String,
         val data: List<Double>,
-        val fill: Boolean = false
+        val fill: Boolean = false,
+        val lineTension: Double = 0.1
 ){
     constructor(label: String, color: String, data: List<Double>): this(label, color, color, data)
 }
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