Updated README to current version of site and added comments to .htaccess

Signed-off-by: Jim Martens <github@2martens.de>

.htaccess

@@ -1,10 +1,13 @@
 RewriteEngine On
 
+# rewrite jim.2martens.de to 2martens.de
 RewriteCond %{HTTP_HOST} ^jim\.2martens\.de [NC]
 RewriteRule ^(.*)$ https://2martens.de/$1 [L,R=301]
 
+# custom 404 error page
 ErrorDocument 404 /404.html
 
+# sets cache header for most static files, max-age is set to one day
 <filesMatch ".(css|jpg|jpeg|png|gif|js|ico|pdf)$">
 Header set Cache-Control "max-age=86400, public"
 </filesMatch>

README.md

@@ -1,6 +1,6 @@
 # Personal Website
 
-[![Build Status](https://travis-ci.org/2martens/2martens.de.png)](https://travis-ci.org/2martens/2martens.de)
+[![Build Status](https://api.travis-ci.org/2martens/2martens.de.png)](https://travis-ci.org/2martens/2martens.de)
 
 This repository hosts my personal website. It is jekyll powered with all required
 dependencies described in the Gemfile. If you wanted, you could create the very same
@@ -19,6 +19,8 @@ what you need to change to make it your own (minimal changes).
 - _data/header-menu.yml: defines the header menu
 - _data/notification.yml: defines the global configuration and if it is visible
 - _data/promotion.yml: defines the promotion and if it is visible
+- _data/cdn.yml: defines whether a CDN is used and what it's URL is
+- _data/lazy-loading.yml: defines whether images are loaded lazily
 - assets/: required static files
 - assets/images/uberspace-badge-*.png: must be changed to accomodate your promotional image
 - assets/images/brand.svg: must be changed to your brand image
@@ -30,6 +32,7 @@ what you need to change to make it your own (minimal changes).
 - pages/: directory for pages, don't forget permalink variable for new pages,
   update every page but 404.html and cv.html to your situation
 - index.html: you should probably update the text here
+- .htaccess: remove the part that rewrites jim.2martens.de to 2martens.de
 
 Beyond this no changes are absolutely necessary. No links are hard-coded in the pages,
 layouts or include files beyond the technical dependencies.
@@ -49,6 +52,22 @@ Without any new files other than posts, these categories are supported out of th
 - blog (appears under Blog menu point)  
 - site (appears on home page)
 
+## Responsive images
+
+If you want to include responsive images in posts, use the following:
+
+```
+{% include image.html alt="<your alt text>" link="<the relative link to the image>" %}
+```
+
+If you have enabled a CDN and are in a production environment (JEKYLL_ENV set to production)
+the URL of the image will use the CDN. Otherwise it will be relative to the root directory
+of the website. The advantage in this approach is quite obvious. If you want to change
+the HTML of an image, you just need to change the image.html and the link to a potential CDN
+only has to be changed in one location and not in potentially thousands of img tags or the 
+markdown equivalent. The HTML provided by image.html automatically adds "img-fluid" to all
+images which makes them responsive by using Bootstrap.
+
 ## Continuous Integration and Deployment
 
 The .travis.yml file is already in a good state to use it for own needs. But you need