Allow base path to be specified for wiki links.

lib/gollum/markup.rb

@@ -202,11 +202,9 @@ module Gollum
       parts = tag.split('|')
       name = parts[0].strip
       cname = Page.cname((parts[1] || parts[0]).strip)
-      if @wiki.page(cname)
-        %{<a class="internal present" href="#{cname}">#{name}</a>}
-      else
-        %{<a class="internal absent" href="#{cname}">#{name}</a>}
-      end
+      link = ::File.join(@wiki.base_path, cname)
+      presence = @wiki.page(cname) ? "present" : "absent"
+      %{<a class="internal #{presence}" href="#{link}">#{name}</a>}
     end
 
     # Find the given file in the repo.

lib/gollum/wiki.rb

@@ -6,6 +6,11 @@ module Gollum
       attr_accessor :page_class, :file_class
     end
 
+    # The String base path to prefix to internal links. For example, when set
+    # to "/wiki", the page "Hobbit" will be linked as "/wiki/Hobbit". Defaults
+    # to "/".
+    attr_reader :base_path
+
     # Public: Initialize a new Gollum Repo.
     #
     # repo    - The String path to the Git repository that holds the Gollum 
@@ -18,6 +23,7 @@ module Gollum
     def initialize(path, options = {})
       @path       = path
       @repo       = Grit::Repo.new(path)
+      @base_path  = options[:base_path] || "/"
       @page_class = options[:page_class] || self.class.page_class
       @file_class = options[:file_class] || self.class.file_class
     end