Only fetch last 100 cadence readings and display as sparklines graph

templates/overview.html

@@ -2,8 +2,11 @@
     class="mb-4 text-4xl font-extrabold leading-none tracking-tight text-gray-900 md:text-5xl lg:text-6xl dark:text-white text-center">
     {{last_cadence}} rpm</h1>
 
-<div class="lg:flex">
-    <img type="image/svg+xml" src={{graph_data|safe}} class="lg:w-3/4 sm:w-full h-1/4" />
+<div class="flex flex-col items-center">
+    
+    <div>
+    {{graph_data|safe}}
+    </div>
 
     <div class="relative overflow-x-auto">
         <table class="lg:w-1/4 sm:w-full text-sm text-left text-gray-500 dark:text-gray-400">