Pass around Roles instead of Strings

Avoid looking up roles by names everywhere. This avoids the awkward
role/role_config naming as well.

test/commander_test.rb

@@ -83,14 +83,14 @@ class CommanderTest < ActiveSupport::TestCase
   end
 
   test "primary_role" do
-    assert_equal "web", @kamal.primary_role
+    assert_equal "web", @kamal.primary_role.name
     @kamal.specific_roles = "workers"
-    assert_equal "workers", @kamal.primary_role
+    assert_equal "workers", @kamal.primary_role.name
   end
 
   test "roles_on" do
-    assert_equal [ "web" ], @kamal.roles_on("1.1.1.1")
-    assert_equal [ "workers" ], @kamal.roles_on("1.1.1.3")
+    assert_equal [ "web" ], @kamal.roles_on("1.1.1.1").map(&:name)
+    assert_equal [ "workers" ], @kamal.roles_on("1.1.1.3").map(&:name)
   end
 
   test "default group strategy" do
@@ -120,7 +120,7 @@ class CommanderTest < ActiveSupport::TestCase
 
     @kamal.specific_roles = [ "web_*" ]
     assert_equal [ "web_chicago", "web_tokyo" ], @kamal.roles.map(&:name)
-    assert_equal "web_tokyo", @kamal.primary_role
+    assert_equal "web_tokyo", @kamal.primary_role.name
     assert_equal "1.1.1.3", @kamal.primary_host
   end
 

test/commands/app_test.rb

@@ -400,6 +400,7 @@ class CommandsAppTest < ActiveSupport::TestCase
 
   private
     def new_command(role: "web", **additional_config)
-      Kamal::Commands::App.new(Kamal::Configuration.new(@config.merge(additional_config), destination: @destination, version: "999"), role: role)
+      config = Kamal::Configuration.new(@config.merge(additional_config), destination: @destination, version: "999")
+      Kamal::Commands::App.new(config, role: config.role(role))
     end
 end

test/configuration_test.rb

@@ -300,14 +300,14 @@ class ConfigurationTest < ActiveSupport::TestCase
   end
 
   test "primary role" do
-    assert_equal "web", @config.primary_role
+    assert_equal "web", @config.primary_role.name
 
     config = Kamal::Configuration.new(@deploy_with_roles.deep_merge({
       servers: { "alternate_web" => { "hosts" => [ "1.1.1.4", "1.1.1.5" ] } },
       primary_role: "alternate_web" } ))
 
 
-    assert_equal "alternate_web", config.primary_role
+    assert_equal "alternate_web", config.primary_role.name
     assert_equal "1.1.1.4", config.primary_host
     assert config.role(:alternate_web).primary?
     assert config.role(:alternate_web).running_traefik?