Merge branch '6419-unify-setup_postgresql.rake' into 'master'

Bring `rake postgresql_md5_hash` to CE

Closes gitlab-ee#6419

See merge request gitlab-org/gitlab-ce!19830

lib/tasks/migrate/setup_postgresql.rake

@@ -22,3 +22,18 @@ task setup_postgresql: :environment do
   ProjectNameLowerIndex.new.up
   AddPathIndexToRedirectRoutes.new.up
 end
+
+desc 'GitLab | Generate PostgreSQL Password Hash'
+task :postgresql_md5_hash do
+  require 'digest'
+  username = ENV.fetch('USERNAME') do |missing|
+    puts "You must provide an username with '#{missing}' ENV variable"
+    exit(1)
+  end
+  password = ENV.fetch('PASSWORD') do |missing|
+    puts "You must provide a password with '#{missing}' ENV variable"
+    exit(1)
+  end
+  hash = Digest::MD5.hexdigest("#{password}#{username}")
+  puts "The MD5 hash of your database password for user: #{username} -> #{hash}"
+end