Call app:boot to rollback

The code in Mrsk::Cli::Main#rollback was very similar to
Mrsk::Cli::App#boot.

Modify Mrsk::Cli::App#boot so it can handle rollbacks by:
1. Only renaming running containers
2. Trying first to start then run the new container

lib/mrsk/commands/app.rb

@@ -6,6 +6,10 @@ class Mrsk::Commands::App < Mrsk::Commands::Base
     @role = role
   end
 
+  def start_or_run
+    combine start, run, by: "||"
+  end
+
   def run
     role = config.role(self.role)
 
@@ -91,8 +95,8 @@ class Mrsk::Commands::App < Mrsk::Commands::Base
     docker :ps, "--quiet", *filter_args(status: :running), "--latest"
   end
 
-  def container_id_for_version(version)
-    container_id_for(container_name: container_name(version))
+  def container_id_for_version(version, only_running: false)
+    container_id_for(container_name: container_name(version), only_running: only_running)
   end
 
   def current_running_version

lib/mrsk/commands/base.rb

@@ -18,8 +18,8 @@ module Mrsk::Commands
       end
     end
 
-    def container_id_for(container_name:)
-      docker :container, :ls, "--all", "--filter", "name=^#{container_name}$", "--quiet"
+    def container_id_for(container_name:, only_running: false)
+      docker :container, :ls, *("--all" unless only_running), "--filter", "name=^#{container_name}$", "--quiet"
     end
 
     private