check for installation on gitweb container

roles/gitweb/tasks/main.yml

@@ -16,6 +16,18 @@
     gitweb_user: gitweb
     gitweb_root: /home/gitweb/projects
     gitweb_stylesheet: custom_highlighting.css
+  block:
+    - name: test if gitweb is already installed
+      find:
+        paths: /etc
+        pattern: gitweb.conf
+      register: check_installed
+
+    - set_fact:
+        install_gitweb: "{{ check_installed.matched == 0 }}"
+
+    - name: install block
+      when: install_gitweb
       block:
       - name: make hash of a random password
         set_fact: