Only pull images if they are not available locally

Avoid excessive downloads and only pull images if needed. This makes the
rollout faster and also helps to reduce traffic when cronjobs are used.

lib/cuber/templates/deployment.yml.erb

@@ -100,7 +100,7 @@ spec:
  containers:
  - name: migration
  image: <%= @options[:image] %>:<%= @options[:release] %>
- imagePullPolicy: Always
+ imagePullPolicy: IfNotPresent
  <%- if @options[:buildpacks] -%>
  command: ["launcher"]
  args: <%= @options[:migrate][:cmd].shellsplit %>
@@ -152,7 +152,7 @@ spec:
  containers:
  - name: <%= procname %>-proc
  image: <%= @options[:image] %>:<%= @options[:release] %>
- imagePullPolicy: Always
+ imagePullPolicy: IfNotPresent
  <%- if @options[:buildpacks] -%>
  command: ["launcher"]
  args: <%= proc[:cmd].shellsplit %>
@@ -202,7 +202,7 @@ spec:
  initContainers:
  - name: migration-check
  image: <%= @options[:image] %>:<%= @options[:release] %>
- imagePullPolicy: Always
+ imagePullPolicy: IfNotPresent
  <%- if @options[:buildpacks] -%>
  command: ["launcher"]
  args: <%= @options[:migrate][:check].shellsplit %>
@@ -257,7 +257,7 @@ spec:
  containers:
  - name: task
  image: <%= @options[:image] %>:<%= @options[:release] %>
- imagePullPolicy: Always
+ imagePullPolicy: IfNotPresent
  <%- if @options[:buildpacks] -%>
  command: ["launcher"]
  args: <%= cron[:cmd].shellsplit %>

lib/cuber/templates/pod.yml.erb

@@ -11,7 +11,7 @@ spec:
  containers:
  - name: pod-proc
  image: <%= @options[:image] %>:<%= @options[:release] %>
- imagePullPolicy: Always
+ imagePullPolicy: IfNotPresent
  command: ["sleep", "infinity"]
  envFrom:
  - configMapRef: