set default for gemmies.dependencies_and_versions

Author: manuelmeurer

db/schema.rb

@@ -256,6 +256,7 @@
 Gemmy.where(dependencies_and_versions_new: nil).update_all "dependencies_and_versions_new = JSON(dependencies_and_versions)"
 ActiveRecord::Migration.remove_column :gemmies, :dependencies_and_versions
 ActiveRecord::Migration.rename_column :gemmies, :dependencies_and_versions_new, :dependencies_and_versions
+ActiveRecord::Migration.change_column_default :gemmies, :dependencies_and_versions, {}
 
 # update compat dependencies keys