Enable LQIP technique in lazy_image_tag with 'min: true' option

cf. LQIP technique https://github.com/aFarkas/lazysizes#lqipblurry-image-placeholderblur-up-image-technique

Author: yasulab

app/views/events/index.html.haml

@@ -4,7 +4,7 @@
 - provide(:meta_image,  "/img/ogp-events.jpeg")
 
 %section.cover
-  = lazy_image_tag 'events_cover.jpg', min: 'events_cover.min.jpg', alt: 'Cover Photo on Upcoming Events'
+  = lazy_image_tag 'events_cover.jpg', alt: 'Cover Photo on Upcoming Events', min: true
 
 %section#events.text-center
   %br

app/views/home/show.html.haml

@@ -5,7 +5,7 @@
   %br
 
 %section.cover
-  = lazy_image_tag '/coderdojo-japan_cover.jpg', min: '/coderdojo-japan_cover.min.jpg', alt: 'CoderDojo Japan カバー画像'
+  = lazy_image_tag '/coderdojo-japan_cover.jpg', alt: 'CoderDojo Japan カバー画像', min: true
 
 %section.introduction.text-center.list
   %p
@@ -39,7 +39,7 @@
     次の動画や記事をぜひ！😆
 
   %div.home-point-thumbnail{style: "margin-top: 30px; margin-bottom: 30px;"}
-    = link_to lazy_image_tag('/video-thumbnail.jpg', min: '/video-thumbnail.min.jpg', alt: 'Promotion Video by CoderDojo Kashiwa'), 'https://www.youtube.com/watch?v=gLDue2xb1j8', target: "_blank", rel: "external noopener"
+    = link_to lazy_image_tag('/video-thumbnail.jpg', alt: 'Promotion Video by CoderDojo Kashiwa', min: true), 'https://www.youtube.com/watch?v=gLDue2xb1j8', target: "_blank", rel: "external noopener"
   /%div.home-point-video
   /  %iframe{allowfullscreen: "", frameborder: "0", height: "315", width: "560",
   /          src: "https://www.youtube.com/embed/gLDue2xb1j8?rel=0"}
@@ -168,7 +168,7 @@
       %a{href: "/kata#support"}<> 『支援』
       をお読みください。
     %div.kata
-      = link_to lazy_image_tag('/kata_cover.jpg', min: '/kata_cover.min.jpg', alt: 'Kata カバー画像', style: 'margin-bottom: 15px;'), '/kata'
+      = link_to lazy_image_tag('/kata_cover.jpg', alt: 'Kata カバー画像', min: true, style: 'margin-bottom: 15px;'), '/kata'
       %a.button-to-details{href: '/kata'} Kata を読む
 
 %section.detail-introduction.partners_logo.text-center#partners{style: "padding-top: 50px;"}

app/views/shared/_header.html.haml

@@ -8,10 +8,8 @@
         %span.icon-bar
         %span.icon-bar
       .navbar-header-logos
-        = link_to lazy_image_tag('/img/header-logo.png',  min: '/img/header-logo.min.png',
-                                 alt: 'CoderDojo logo'),  '/', id: "header-logo"
-        = link_to lazy_image_tag('/img/header-brand.png', min: '/img/header-brand.min.png',
-                                 alt: 'CoderDojo brand'), '/', id: "header-brand"
+        = link_to lazy_image_tag('/img/header-logo.png',  alt: 'CoderDojo logo',  min: true), '/', id: "header-logo"
+        = link_to lazy_image_tag('/img/header-brand.png', alt: 'CoderDojo brand', min: true), '/', id: "header-brand"
     #bs-example-navbar-collapse-1.collapse#header-nav-toggle.navbar-collapse
       %ul.nav.navbar-nav.navbar-right
         %li= link_to '全国の道場',     '/#dojos'