prepare Supervisor for RQ
add rq-worker supervisor Jinja2 template
prepare for rq scheduler usage in Vagrant
start rq scheduler in production setups
install nginx on vagrant production
add some more documentation
remove production vagrant on this branch for now
Merge pull request #955 from PyBossa/vagrant-rq

Vagrant RQ
Merge branch 'master' into issue-repositories

* master:
  remove production vagrant on this branch for now
  add some more documentation
  install nginx on vagrant production
  start rq scheduler in production setups
  prepare for rq scheduler usage in Vagrant
  add rq-worker supervisor Jinja2 template
  prepare Supervisor for RQ
Simplify Vagrant and Ansible file

Speedup: Remove installation of latest Ansible with PPA. Made provisioning
compatible with older Ansible versions from the Ubuntu repositories.
Simplify: Vagrant files. Remove different groups which are not used.
Vagrant also does not support options. Better put production based Ansible
provisioning in a seperate repo. Vagrant should be only used for local dev
instances and is not a good solution for real server provisioning.
Remove also group vars.
add note regarding virtualenv
Merge pull request #959 from PyBossa/issue-simplify-vagrant-ansible

Issue simplify vagrant ansible
Merge pull request #859 from PyBossa/issue-repositories

Refactor repositories
Delete associated taskruns when deleting tasks
Test project dependant resources are deleted when deleting project
Merge pull request #961 from PyBossa/issue-delete-tasks

Issue delete tasks
Add limit and offset to task repository filter_by methods
Add limit and offset to all repositories filter_by and order result
Use limit and offset in repository method calls in API
Delete file commited by mistake