RUBY-1291 Add note to README about setting ENV var when tests with external connections should be skipped
RUBY-1291 Add note to README about setting ENV var when tests with external connections should be skipped

saghm/mongo-ruby-driver,mongodb/mongo-ruby-driver,saghm/mongo-ruby-driver,mongodb/mongo-ruby-driver,mongodb/mongo-ruby-driver,jonhyman/mongo-ruby-driver,jonhyman/mongo-ruby-driver