Update modify command to properly handle tags and TTL

lib/vmfloaty.rb

@@ -91,7 +91,7 @@ class Vmfloaty
       c.syntax = 'floaty modify [hostname]'
       c.summary = 'Modify a vms tags and TTL'
       c.description = ''
-      c.example 'description', 'command example'
+      c.example 'Modifies myhost1 to have a TTL of 12 hours and adds a custom tag', 'floaty modify myhost1 --lifetime 12 --url https://myurl --token mytokenstring --tags \'{"tag":"myvalue"}\''
       c.option '--verbose', 'Enables verbose output'
       c.option '--url STRING', String, 'URL of vmpooler'
       c.option '--token STRING', String, 'Token for vmpooler'

lib/vmfloaty/pooler.rb

@@ -34,15 +34,20 @@ class Pooler
   end
 
   def self.modify(verbose, url, hostname, token, lifetime, tags)
-    modify_body = {'lifetime'=>lifetime, 'tags'=>tags}
+    modify_body = {}
+    if lifetime
+      modify_body['lifetime'] = lifetime
+    end
+    if tags
+      modify_body['tags'] = tags
+    end
+
+    puts modify_body
     conn = Http.get_conn_with_token(verbose, url, token)
     conn.headers['X-AUTH-TOKEN']
 
-    response = conn.put do |req|
-      req.url "/vm/#{hostname}"
-    end
+    response = conn.put "/vm/#{hostname}"
     res_body = JSON.parse(response.body)
-
     res_body
   end