add custom style example

see #27 and #28

features/bibtex.feature

@@ -185,3 +185,29 @@ Feature: BibTeX
     And the "_site/scholar.html" file should exist
     And I should not see "ruby" in "_site/scholar.html"
     And I should see "id=\"a-smalltalk\"" in "_site/scholar.html"
+
+  @tags @bibliography @style
+  Scenario: Simple Bibliography Loaded From Default Directory
+    Given I have a scholar configuration with:
+      | key    | value             |
+      | source | ./_bibliography   |
+    And I have a "_bibliography" directory
+    And I have a file "_bibliography/references.bib":
+      """
+      @book{ruby,
+        title     = {The Ruby Programming Language},
+        author    = {Flanagan, David and Matsumoto, Yukihiro},
+        year      = {2008},
+        publisher = {O'Reilly Media}
+      }
+      """
+    And I have a page "scholar.html":
+      """
+      ---
+      ---
+      {% bibliography  --style mla %}
+      """
+    When I run jekyll
+    Then the _site directory should exist
+    And the "_site/scholar.html" file should exist
+    And I should see "<i>The Ruby Programming Language</i>. O’Reilly Media, 2008" in "_site/scholar.html"