add interval for seconds for bar charts

pdb-plotting/src/main/java/org/lucares/pdb/plot/api/Interval.java

@@ -28,6 +28,8 @@ public class Interval {
 
     private String toDateFormatForBucketer(final IntervalTimeUnit intervalTimeUnit) {
         switch (intervalTimeUnit) {
+        case SECOND:
+            return "yyyy-MM-dd'\\n'HH:mm:ss";
         case MINUTE:
             return "yyyy-MM-dd'\\n'HH:mm";
         case HOUR:

pdb-plotting/src/main/java/org/lucares/pdb/plot/api/IntervalTimeUnit.java

@@ -3,7 +3,7 @@ package org.lucares.pdb.plot.api;
 import org.lucares.utils.DateBucketUnit;
 
 public enum IntervalTimeUnit {
-    MINUTE, HOUR, DAY, WEEK, MONTH, YEAR;
+    SECOND, MINUTE, HOUR, DAY, WEEK, MONTH, YEAR;
 
     public static boolean isValid(final String value) {
         for (final IntervalTimeUnit e : values()) {
@@ -16,6 +16,8 @@ public enum IntervalTimeUnit {
 
     public DateBucketUnit toChronoUnit() {
         switch (this) {
+        case SECOND:
+            return DateBucketUnit.SECOND;
         case MINUTE:
             return DateBucketUnit.MINUTE;
         case HOUR: