feat(i18n): Add missing sk translations.

Missing translations on grouping feature are breaking the grid.

Author: edesr1988

src/js/i18n/sk.js

@@ -57,6 +57,16 @@
           invalidCsv: 'File was unable to be processed, is it valid CSV?',
           invalidJson: 'File was unable to be processed, is it valid Json?',
           jsonNotArray: 'Imported json file must contain an array, aborting.'
+        },
+        grouping: {
+          group: 'Group',
+          ungroup: 'Ungroup',
+          aggregate_count: 'Agg: Count',
+          aggregate_sum: 'Agg: Sum',
+          aggregate_max: 'Agg: Max',
+          aggregate_min: 'Agg: Min',
+          aggregate_avg: 'Agg: Avg',
+          aggregate_remove: 'Agg: Remove'
         }
       });
       return $delegate;