diff --git a/share/rubygems/generate b/share/rubygems/generate
index b23bd0d581..3e5fc77d2d 100755
--- a/share/rubygems/generate
+++ b/share/rubygems/generate
@@ -19,15 +19,15 @@
 require 'fileutils'
 require 'tmpdir'
 
-VERSION = "5.12.13"
+VERSION = '5.12.13'
 
 def version
     v = VERSION
 
-    _, min, incr = v.split(".").collect{|e| e.to_i}
+    _, min, incr = v.split('.').collect {|e| e.to_i }
 
     if min >= 80 || incr >= 80
-        v += ".pre"
+        v += '.pre'
     end
 
     v
@@ -35,29 +35,29 @@ end
 
 DEFAULTS={
     :version => version,
-    :date => Time.now.strftime("%Y-%m-%d"),
+    :date => Time.now.strftime('%Y-%m-%d'),
     :dependencies => []
 }
 
-TEMPLATE=<<EOT
-# This file is automatically generated
+TEMPLATE=<<~EOT
+    # This file is automatically generated
 
-Gem::Specification.new do |s|
-  s.name        = '$(NAME)'
-  s.version     = '$(VERSION)'
-  s.date        = '$(DATE)'
-  s.summary     = "$(SUMMARY)"
-  s.description = "$(DESCRIPTION)"
-  s.authors     = ["OpenNebula"]
-  s.email       = 'contact@opennebula.io'
-  s.license     = 'Apache-2.0'
-  s.files       = [
-$(FILES)
-  ]
-  s.homepage    = 'http://opennebula.io'
-$(EXECUTABLES)
-$(DEPENDENCIES)
-end
+    Gem::Specification.new do |s|
+      s.name        = '$(NAME)'
+      s.version     = '$(VERSION)'
+      s.date        = '$(DATE)'
+      s.summary     = "$(SUMMARY)"
+      s.description = "$(DESCRIPTION)"
+      s.authors     = ["OpenNebula"]
+      s.email       = 'contact@opennebula.io'
+      s.license     = 'Apache-2.0'
+      s.files       = [
+    $(FILES)
+      ]
+      s.homepage    = 'http://opennebula.io'
+    $(EXECUTABLES)
+    $(DEPENDENCIES)
+    end
 
 EOT
 
@@ -77,6 +77,10 @@ GEM_DESCRIPTION={
             ['src/mad/ruby/ActionManager.rb', '/lib'],
             ['src/mad/ruby/DriverExecHelper.rb', '/lib'],
 
+            # other depenencies
+            ['src/flow/lib/models.rb', '/lib'],
+            ['src/flow/lib/models/*.rb', '/lib/models'],
+
             ['src/oca/ruby/opennebula/*.rb', '/lib/opennebula'],
             ['src/authm_mad/remotes/**/*.rb', '/lib/opennebula'],
             ['src/cloud/common/CloudClient.rb', '/lib/cloud'],
@@ -88,7 +92,10 @@ GEM_DESCRIPTION={
         :dependencies => [
             'nokogiri',
             'json',
-            'rbvmomi'
+            'rbvmomi',
+            'treetop', # oneflow
+            'ipaddress',  # oneflow
+            'parse-cron'  # oneflow
         ]
     },
 
@@ -114,18 +121,18 @@ def sane_prefix(prefix)
 
     p=prefix
 
-    p.slice!(0) if p[0,1]=='/'
-    p<<'/' if p[-1,1]!='/'
+    p.slice!(0) if p[0, 1]=='/'
+    p<<'/' if p[-1, 1]!='/'
 
     p
 end
 
 def file_list(description)
-    files=Array.new
+    files=[]
 
     description[:files].each do |f, prefix, exclude|
         Dir.glob(f).each do |source|
-            next if (! exclude.nil?) and (source.match(exclude))
+            next if !exclude.nil? and source.match(exclude)
 
             files << [source, sane_prefix(prefix)+File.basename(source)]
         end
@@ -134,14 +141,14 @@ def file_list(description)
     files
 end
 
-def copy_files(files, source_prefix='', destination_prefix='')
+def copy_files(files, source_prefix = '', destination_prefix = '')
     files.each do |file|
         source=source_prefix+file[0]
         destination=destination_prefix+file[1]
 
         dir=File.dirname destination
 
-        FileUtils.mkdir_p(dir) if !File.exist?(dir)
+        FileUtils.mkdir_p(dir) unless File.exist?(dir)
 
         FileUtils.cp(source, destination)
     end
@@ -154,10 +161,10 @@ def generate_gem_file_list(files)
 end
 
 def generate_gem_executable_list(files)
-    executables=files.
-        select {|f| f.last.match(/^bin\//) }.
-        map {|f| "'#{File.basename(f.last)}'" }.
-        join(", ")
+    executables=files
+                .select {|f| f.last.match(%r{^bin/}) }
+                .map {|f| "'#{File.basename(f.last)}'" }
+                .join(', ')
 
     if !executables.empty?
         "  s.executables=[#{executables}]"
@@ -168,9 +175,9 @@ end
 
 def generate_dependencies(dependencies)
     dependencies.map do |d|
-        line="  s.add_runtime_dependency "
-        if Array===d
-            line<<d.map {|part| "'#{part}'" }.join(", ")
+        line='  s.add_runtime_dependency '
+        if d.is_a?(Array)
+            line<<d.map {|part| "'#{part}'" }.join(', ')
         else
             line<<"'#{d}'"
         end
@@ -188,7 +195,8 @@ def populate_gem_template(description, files)
             generate_gem_file_list(files)
         elsif var==:dependencies
             generate_dependencies(
-                description[:dependencies]||DEFAULTS[:dependencies])
+                description[:dependencies]||DEFAULTS[:dependencies]
+            )
         elsif var==:executables
             generate_gem_executable_list(files)
         elsif description[var]
@@ -200,7 +208,7 @@ def populate_gem_template(description, files)
 end
 
 def generate_gem_file(gem_file, description, files)
-    File.open(gem_file, "w") do |f|
+    File.open(gem_file, 'w') do |f|
         f.write(populate_gem_template(description, files))
     end
 end
@@ -208,22 +216,22 @@ end
 def generate_gem(description)
     Dir.mktmpdir do |tmp|
         files=file_list(description)
-        copy_files(files, '', tmp+"/")
+        copy_files(files, '', tmp+'/')
 
-        gem_file=tmp+"/gem.gemspec"
+        gem_file=tmp+'/gem.gemspec'
         generate_gem_file(gem_file, description, files)
 
         pwd=Dir.pwd
 
         Dir.chdir(tmp) do
-            system("gem build gem.gemspec")
+            system('gem build gem.gemspec')
 
             if $?.exitstatus!=0
-                puts "Error generating gem"
+                puts 'Error generating gem'
                 exit(-1)
             end
 
-            Dir.glob("*.gem").each do |f|
+            Dir.glob('*.gem').each do |f|
                 FileUtils.cp(f, pwd)
             end
         end
@@ -232,8 +240,7 @@ end
 
 # Go to source code root dir
 root=Dir.pwd
-root.gsub!(/\/share\/rubygems$/, '')
+root.gsub!(%r{/share/rubygems$}, '')
 Dir.chdir(root)
 
-
-GEM_DESCRIPTION.each {|name, gem| generate_gem(gem) }
+GEM_DESCRIPTION.each {|_name, gem| generate_gem(gem) }