Fixes the following warning:
```
dpkg: warning: parsing file '/var/lib/dpkg/tmp.ci/control' near line 6 package 'dokku':
`Depends' field, reference to `lxc-docker':
`>' is obsolete, use `>=' or `>>' instead
```
Refs #1776
The python version should allow us to remove any ruby dependencies and should also slightly speed up dokku installation. All LSB-compliant distributions should have python, so we should be okay depending upon it.
Closes#1783Closes#1786
The version of docker.io in jessie-backports is 1.6.2~dfsg1-1~bpo8+1.
This is regarded as lower than 1.6.2 by dpkg because `~` has a special meaning
in regards to version sort in dpkg.
This leads to:
```
The following packages have unmet dependencies:
dokku : Depends: docker-engine-cs but it is not installable or
docker-engine but it is not installable or
lxc-docker (>= 1.6.2) but it is not installable or
docker.io (>= 1.6.2) but 1.6.2~dfsg1-1~bpo8+1 is to be installed
Recommends: herokuish but it is not going to be installed
```
By changing the contraints the version in backports will be accepted by dpkg.
Changing the herokuish package to Recommends instead of Depends allows users to skip the installation of that package by specifying --no-install-recommends. Herokuish will still be installed by default using apt-get
* Bump `Version` field.
* Set minimum nginx version to 1.4.6, per #1654
* Depend on both `rubygem-foo` (Ubuntu) and `ruby-foo` (Debian).
* Add distro-default `docker.io (>= 1.6.2)` as an alternative.
Version 1.6.2 is in both `trusty-updates` and `jessie-backports`,
while `trusty` itself has `0.9.1`. We seriously want to avoid that.
This also updates the docs so people don't forget to bump the version
field in the future. Even though we really do that for them with sed.
This will allow developers to run an `upgrade` on existing installations without breaking because docker-engine isn't yet in their apt lists...
[ci skip]
This should allow installation of the dokku packages on debian jessie. Upstream docker created this package in response to an issue where `cgroup-bin` could not be installed at the same time as lxc.
Closes#1236
Refs #1076
[ci skip]
