set port from .env if specified

lib/foreman/engine.rb

@@ -84,7 +84,7 @@ private ######################################################################
   end
 
   def base_port
-    options[:port] || 5000
+    options[:port] || environment["PORT"] || 5000
   end
 
   def kill_all(signal="SIGTERM")

spec/foreman/engine_spec.rb

@@ -100,6 +100,13 @@ describe "Foreman::Engine", :fakefs do
       engine.start
     end
 
+    it "should set port from .env if specified" do
+      File.open(".env", "w") { |f| f.puts("PORT=8017") }
+      engine = Foreman::Engine.new("Procfile")
+      engine.send(:base_port).should == "8017"
+      engine.start
+    end
+
     it "should be loaded relative to the Procfile" do
       FileUtils.mkdir_p "/some/app"
       File.open("/some/app/.env", "w") { |f| f.puts("FOO=qoo") }