Add workouts

app/templates/workouts/index.html.slim

@@ -0,0 +1,12 @@
+div class="mb-12 prose dark:prose-invert max-w-prose mx-auto text-gray-800 dark:text-gray-200"
+  h1 Hikes
+
+div class="max-w-prose mx-auto"
+  - workouts_by_year.each do |year, workouts|
+    h3= year
+    h1= "#{(workouts.map{|w| w.distance }.sum / 1000).round} km"
+    div class="grid grid-cols-3 gap-4 mb-4 max-w-prose mx-auto"
+      - workouts.each do |workout|
+        == workout.path
+
+div class="max-w-screen-md mx-auto border-t-4 border-solid border-gray-400 dark:border-gray-600"