Initial implementation of a git repository button

src/config.rs

@@ -440,6 +440,8 @@ pub struct HtmlConfig {
     pub no_section_label: bool,
     /// Search settings. If `None`, the default will be used.
     pub search: Option<Search>,
+    /// Git repository url. If 'None', the git button will not be shown.
+    pub git_repository_url: Option<String>,
 }
 
 impl HtmlConfig {

src/renderer/html_handlebars/hbs_renderer.rs

@@ -454,6 +454,10 @@ fn make_data(
         )
     }
 
+    if let Some(ref git_repository_url) = html_config.git_repository_url {
+        data.insert("git-repository-url".to_owned(), json!(git_repository_url));
+    }
+
     let mut chapters = vec![];
 
     for item in book.iter() {

src/theme/css/chrome.css

@@ -63,9 +63,12 @@ a > .hljs {
     margin: 0;
 }
 
-#print-button {
+.right-buttons {
     margin: 0 15px;
 }
+.right-buttons a {
+    text-decoration: none;
+}
 
 html:not(.sidebar-visible) #menu-bar:not(:hover).folded > #menu-bar-sticky-container {
     transform: translateY(-60px);

src/theme/index.hbs

@@ -113,6 +113,11 @@
                             <a href="{{ path_to_root }}print.html" title="Print this book" aria-label="Print this book">
                                 <i id="print-button" class="fa fa-print"></i>
                             </a>
+                            {{#if git-repository-url}}
+                            <a href="{{git-repository-url}}" title="Git repository" aria-label="Git repository">
+                                <i id="github-button" class="fa fa-git"></i>
+                            </a>
+                            {{/if}}
                         </div>
                     </div>
                 </div>