add .Site.Params.since

.Site.Params.since is an option to store the year site development
started:
(c) 2019 - 2020

exampleSite/config.toml

@@ -24,6 +24,7 @@ theme = "hyde-hyde"
 
     # sidebar, copyright & license
     copyright = "htr3n"
+    since = 2019
     license = "CC BY-SA 4.0"
     licenseURL = "https://creativecommons.org/licenses/by-sa/4.0"
     showBuiltWith = true

layouts/partials/sidebar/copyright.html

@@ -1,6 +1,6 @@
 {{ with .Site.Params.copyright }}
 <div class="copyright">
-  &copy; {{ now.Format "2006"}} {{ . | safeHTML }}
+  &copy; {{ with $.Site.Params.since }}{{ if lt . now.Year }}{{ . | safeHTML }} - {{ end }}{{ end }}{{ now.Format "2006"}} {{ . | safeHTML }}
   {{ with $.Site.Params.license }}
     <a href="{{$.Site.Params.licenseURL | safeHTML}}">{{ . | safeHTML }}</a>
   {{end}}