Update hacker readme

README.md

 # blog-memopol
-Blog about Memopol and its news. In Pelican.
 
-#config
-You'll need to change some config settings, like the folder, the username, the theme folder.
+Clone the project::
 
-#theme
+    git clone --recursive gitlab@git.laquadrature.net:political-memory/blog-memopol.git
+
+Install pelican::
+
+    pip install pelican
+    # Or use apt or your favorite package manager
+
+If you have this error::
+
+    CRITICAL: UndefinedError: 'extra_siteurls' is undefined
+
+Then it means that the plugins directory is not populated, to do so::
+
+    git submodule update --init
+    # Or, next time do git clone with --recursive
+
+The command to generate the output is::
+
+    pelican
+    # Or, if you're developping, use this command and open localhost:8000
+    make devserver
+
+
+# theme
 
 The theme is based on bootstrap4. To hack it::
 
@@ -19,6 +40,7 @@ The theme is based on bootstrap4. To hack it::
     # Then you need to run the pelican command again in the parent directory
     cd ../ && pelican
 
-#plugins
-I use the pin to top plugin to have a sticky article on homepage.
-It's already on github, here : https://github.com/Shaked/pin_to_top
+# plugins
+
+Don't forget to checkout submodules, ie. with
+``git submodule sync; git submodule init --update``