Merge pull request #4 from mtpereira/debian_repos

Debian repos
Add postgis support
Correct pg_ident.conf file name
Change running to started @jdauphant fix
Stop default postgresql in travis VM @jdauphant fix
Try to remove postgresql before install
Update main.yml
Update README.md
Now using apt.postgresql.org for all Debians.

tasks/main.yml:
- Includes tasks/debian.yml if ansible_os_family is Debian, in
  order to always use apt.postgresql.org for Debians.

tasks/ubuntu.yml:
- No longer used, removed.
Merge pull request #5 from mtpereira/fix_ubuntu_repo

Now using apt.postgresql.org for all Debians.