roles/taiga: Deploy Taiga project management app

The *taiga* role installs the three components of Taiga:

* taiga-back
* taiga-events
* taiga-front

*taiga-back* is a Python application. Its dependencies are installed via
`pip` in the *taiga* user's site-packages, and the application itself is
installed by unpacking the archive. *taiga-events* is a Node.js
application. Its dependencies are installed by `npm`, and is itself
installed by unpacking the archive. Finally, *taiga-front* is a
single-page browser application that is installed by unpacking the
archive, and served by Apache.

Taiga requires PostgreSQL and RabbitMQ.

roles/taiga/handlers/main.yml

@@ -0,0 +1,34 @@
+- name: reload systemd
+  command: systemctl daemon-reload
+
+- name: migrate taiga data
+  become: true
+  become_user: taiga
+  command:
+    /usr/local/lib/taiga/venv/bin/python manage.py migrate
+    chdir=/usr/local/lib/taiga/taiga-back
+- name: compile taiga messages
+#  become: true
+#  become_user: taiga
+  command:
+    /usr/local/lib/taiga/venv/bin/python manage.py compilemessages
+    chdir=/usr/local/lib/taiga/taiga-back
+- name: collect taiga static data
+#  become: true
+#  become_user: taiga
+  command:
+    /usr/local/lib/taiga/venv/bin/python manage.py collectstatic --noinput
+    chdir=/usr/local/lib/taiga/taiga-back
+
+- name: reload httpd
+  service:
+    name: httpd
+    state: reloaded
+- name: restart taiga-events
+  service:
+    name: taiga-events
+    state: restarted
+- name: restart taiga
+  service:
+    name: taiga
+    state: restarted