README : add composer.json content to install DomFramework from Git repository

README.md

@@ -4,4 +4,20 @@
 This library is small : one feature in one file.
 Well tested, developped from 2005 without interruption.
 
-# Install from Composer !
+# Install from Composer
+Create a composer.json file with content :
+```
+{
+   "name": "mynamespace/my-project-that-uses-composer",
+   "repositories": [
+       {
+           "name": "dominique.fournier/domframework",
+           "type": "vcs",
+           "url": "https://git.fournier38.fr/Dominique.Fournier/DomFramework.git"
+       }
+    ],
+    "require": {
+        "dominique.fournier/domframework": "dev-master"
+    }
+}
+```