Installation-manual.md

@@ -57,11 +57,7 @@ yarn install
 
 When promted for the password enter the highly secure string `chouette`.
 
-## Rails
-
-### Dependencies
-
-As documented [here](https://github.com/dryade/georuby-ext/issues/2) we need some more libs before we can start the `rake` setup tasks.
+As documented [here](https://github.com/dryade/georuby-ext/issues/2) we need some more libs before we can use database : 
 
 On mac/OS :
 
@@ -75,6 +71,14 @@ On debian/ubuntu system :
 sudo apt-get install libproj-dev postgis
 ```
 
+## Rails
+
+### Dependencies
+
+```sh
+sudo apt-get install libmagickwand-dev
+```
+
 ### Install gems
 
 Add the bundler gem