Well, that's Git integration working. Not complete; it ought to be possible

to view the log of the current page, and previous versions - but it's a start.

.gitignore

@@ -6,6 +6,7 @@ pom.xml.asc
 /classes/
 /target/
 /checkouts/
+/resources/public/content/.git
 .lein-deps-sum
 .lein-repl-history
 .lein-plugins/

project.clj

@@ -1,4 +1,4 @@
-(defproject smeagol "0.1.0-SNAPSHOT"
+(defproject smeagol "0.2.0-SNAPSHOT"
   :description "A simple Git-backed Wiki inspired by Gollum"
   :url "http://example.com/FIXME"
   :dependencies [[org.clojure/clojure "1.6.0"]
@@ -7,8 +7,8 @@
                  [selmer "0.7.2"]
                  [com.taoensso/timbre "3.3.1"]
                  [com.taoensso/tower "3.0.2"]
-                 [markdown-clj "0.9.55"
-                  :exclusions [com.keminglabs/cljx]]
+                 [markdown-clj "0.9.55" :exclusions [com.keminglabs/cljx]]
+                 [clj-jgit "0.8.1"]
                  [environ "1.0.0"]
                  [im.chit/cronj "1.4.2"]
                  [noir-exception "0.2.2"]

resources/public/content/Introduction.md

@@ -2,7 +2,7 @@
 
 Smeagol is a simple Wiki engine inspired by [Gollum](https://github.com/gollum/gollum/wiki). Gollum is a Wiki engine written in Ruby, which uses a number of simple text formats including [Markdown](http://daringfireball.net/projects/markdown/), which uses [Git](http://git-scm.com/) to provide versioning and backup. I needed a new Wiki for a project and thought Gollum would be ideal - but unfortunately it doesn't provide user authentication, which I needed, and it was simpler for me to reimplement the bits I did need in Clojure than to modify Gollum.
 
-So at this stage Smeagol is a Wiki engine written in Clojure which uses Markdown as its text format, which does have user authentication, and which will soon use Git as its versioning and backup system.
+So at this stage Smeagol is a Wiki engine written in Clojure which uses Markdown as its text format, which does have user authentication, and which uses Git as its versioning and backup system.
 
 ## Markup syntax
 
@@ -10,15 +10,15 @@ Smeagol uses the Markdown format as provided by [markdown-clj](https://github.co
 
 ## Security and authentication
 
-Currently security is very weak. There is currently a file called *passwd* in the *resources/public* directory, which contains a clojure map of username/plain-text password pairs thus:
+Currently security is very weak. There is currently a file called *passwd* in the *resources/public* directory, which contains a clojure map of which maps username to maps with plain-text passwords and emails thus:
 
-    {:admin "admin"}
+    {:admin {:password "admin" :email "admin@localhost"}
+     :adam {:password "secret" :email "adam@localhost"}}
 
 that is to say, the username is a keyword and the corresponding password is a string. Obviously, this is a temporary solution while in development which I will fix later.
 
 ## Todo
 
-* Git integration! Smeagol doesn't have any inbuilt versioning or backup mechanism; it's intended that Git will be used as that mechanism. But it isn't implemented yet;
 * Image (and other media) upload;
 * Improved editor. The editor is at present very primitive - right back from the beginnings of the Web. It would be nice to have a rich embedded editor like [Hallo](https://github.com/bergie/hallo) or [Aloha](http://aloha-editor.org/Content.Node/index.html) but I havenven't (yet) had time to integrate them!
 * Improved security. Having the passwords in plain text rather than encrypted is just basically poor; having the passwd file in *public* space is also poor (although I believe it cannot be accessed via HTTP). Essentially, authentication mechanisms should be pluggable, and at present they aren't; 

resources/public/passwd

@@ -1 +1,2 @@
-{:admin "admin"}
+{:admin {:password "admin" :email "admin@localhost"}}
+

resources/templates/edit.html

@@ -11,6 +11,11 @@
         <form action="{{servlet-context}}/edit" method="POST">
             <input type="hidden" name="content" value="{{title}}"/>
             <textarea name="src" id="src" rows="25" cols="80">{{content}}</textarea>
+        	<p class="widget">
+                <label for="summary">What have you changed?</label>
+                <input name="summary" id="summary" type="text" 
+                	value="{%if exists%}{%else%}New file {{title}}{%endif%}"/>
+        	</p>
             <p class="widget">
                 <label for="submit">When you have finished editing</label>
                 <input name="submit" id="submit" type="submit" class="action" value="Save!"/>

src/smeagol/authenticate.clj

@@ -1,10 +1,34 @@
 (ns smeagol.authenticate (:require [noir.io :as io]))
 
+;; Smeagol: a very simple Wiki engine
+;; Copyright (C) 2014 Simon Brooke
+
+;; This program is free software; you can redistribute it and/or
+;; modify it under the terms of the GNU General Public License
+;; as published by the Free Software Foundation; either version 2
+;; of the License, or (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program; if not, write to the Free Software
+;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
 (defn authenticate
-  "Return true if this username/password pair match, false otherwise"
+  "Return `true` if this `username`/`password` pair match, `false` otherwise"
   [username password]
   (let [path (str (io/resource-path) "passwd")
         users (read-string (slurp path))
         user (keyword username)]
-    (println (str "Checking for user " user " with password " password " in " users " from " path))
-    (.equals (user users) password)))
+    (.equals (:password (user users)) password)))
+
+(defn get-email
+  "Return the email address associated with this `username`."
+  [username]
+  (let [path (str (io/resource-path) "passwd")
+        users (read-string (slurp path))
+        user (keyword username)]
+    (:email (user users))))

src/smeagol/routes/wiki.clj

@@ -18,6 +18,7 @@
 (ns smeagol.routes.wiki
   (:use clojure.walk)
   (:require [compojure.core :refer :all]
+            [clj-jgit.porcelain :as git]
             [noir.io :as io]
             [noir.response :as response]
             [noir.util.route :as route]
@@ -27,11 +28,21 @@
             [smeagol.util :as util]))
 
 (defn process-source
-  "Process `source-text` and save it to the specified `file-path`, finally redirecting to wiki-page"
-  [file-path source-text request]
-  (let [params (keywordize-keys (:params request))
-        content (or (:content params) "Introduction")]
+  "Process `source-text` and save it to the specified `file-path`, committing it
+   to Git and finally redirecting to wiki-page."
+  [params]
+  (let [source-text (:src params)
+        content (:content params)
+        file-name (str content ".md")
+        file-path (str (io/resource-path) "/content/" file-name)
+        exists? (.exists (clojure.java.io/as-file file-path))
+        git-repo (git/load-repo (str (io/resource-path) "/content/.git"))
+        user (session/get :user)
+        email (auth/get-email user)
+        summary (:summary params)]
     (spit file-path source-text)
+    (if (not exists?) (git/git-add git-repo file-name))
+    (git/git-commit git-repo summary {:name user :email email})
     (response/redirect (str "/wiki?" content))
   ))
 
@@ -45,14 +56,15 @@
         file-name (str "/content/" content ".md")
         file-path (str (io/resource-path) file-name)
         exists? (.exists (clojure.java.io/as-file file-path))]
-    (cond src-text (process-source file-path src-text request)
+    (cond src-text (process-source params)
           true
           (layout/render "edit.html"
                    {:title content
                     :left-bar (util/md->html "/content/_edit-left-bar.md")
                     :header (util/md->html "/content/_header.md")
                     :content (if exists? (io/slurp-resource file-name) "")
-                    :user (session/get :user)}))))
+                    :user (session/get :user)
+                    :exists exists?}))))
 
 (defn local-links
   "Rewrite text in `html-src` surrounded by double square brackets as a local link into this wiki."