Make Remote#hostname attribute read-only

lib/producer/core/remote.rb

@@ -4,7 +4,7 @@ module Producer
       require 'etc'
       require 'net/ssh'
 
-      attr_accessor :hostname
+      attr_reader :hostname
 
       def initialize(hostname)
         @hostname = hostname

spec/producer/core/remote_spec.rb

@@ -5,8 +5,8 @@ module Producer::Core
     let(:hostname)    { 'some_host.example' }
     subject(:remote)  { Remote.new(hostname) }
 
-    describe '#hostname' do
-      it 'returns the assignated hostname' do
+    describe '#initialize' do
+      it 'assigns the given hostname' do
         expect(remote.hostname).to eq hostname
       end
     end