fix: Fixed broken migration_command default

Due to construction of the old migration command, in very rare scenarios
it could invoke the `db:setup` command despite the database being set.
This could wipe out the database with productional data. The fix
ensures, that either migration command or setup command are ran - never
both.

Resolves #58

attributes/default.rb

@@ -99,8 +99,10 @@
 
 default['defaults']['framework']['migrate'] = true
 default['defaults']['framework']['migration_command'] =
-  '/usr/local/bin/bundle exec rake db:version > /dev/null 2>&1 ' \
-  '&& /usr/local/bin/bundle exec rake db:migrate || /usr/local/bin/bundle exec rake db:setup'
+  'if /usr/local/bin/bundle exec rake db:version > /dev/null 2>&1; ' \
+  'then /usr/local/bin/bundle exec rake db:migrate; ' \
+  'else /usr/local/bin/bundle exec rake db:setup; ' \
+  'fi'
 default['defaults']['framework']['assets_precompile'] = true
 default['defaults']['framework']['assets_precompilation_command'] = '/usr/local/bin/bundle exec rake assets:precompile'
 default['defaults']['framework']['envs_in_console'] = false