Add support for setting environment variables

data/export/launchd/launchd.plist.erb

@@ -4,6 +4,13 @@
 <dict>
     <key>Label</key>
     <string><%= "#{app}-#{name}-#{num}" %></string>
+    <key>EnvironmentVariables</key>
+    <dict>
+    <% engine.env.merge("PORT" => port).each_pair do |var,env| %>
+      <key><%= var.upcase %></key>
+      <string><%= env %></string>
+    <% end %>
+    </dict>
     <key>ProgramArguments</key>
     <array>
         <string><%= process.command %></string>

spec/resources/export/launchd/launchd-a.default

@@ -4,6 +4,13 @@
 <dict>
     <key>Label</key>
     <string>app-alpha-1</string>
+    <key>EnvironmentVariables</key>
+    <dict>
+    
+      <key>PORT</key>
+      <string>5000</string>
+    
+    </dict>
     <key>ProgramArguments</key>
     <array>
         <string>./alpha</string>

spec/resources/export/launchd/launchd-b.default

@@ -4,6 +4,13 @@
 <dict>
     <key>Label</key>
     <string>app-bravo-1</string>
+    <key>EnvironmentVariables</key>
+    <dict>
+    
+      <key>PORT</key>
+      <string>5000</string>
+    
+    </dict>
     <key>ProgramArguments</key>
     <array>
         <string>./bravo</string>