Log Message:
devel/ruby-railties51: update to 5.1.6

## Rails 5.1.6 (March 29, 2018) ##

*   Fix check for minimum Ruby version to correctly identify Ruby 2.2.10.

    *shia*

*   Fix minitest rails plugin.

    The custom reporters are added only if needed.

    This will fix conflicts with others plugins.

    *Kevin Robatel*