Gemfile in zold-0.0.5 vs Gemfile in zold-0.0.6

@@ -17,6 +17,7 @@
 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
 source 'https://rubygems.org'
+ruby '2.3.3'
 gemspec