Initialize the Gemfile.next.lock

We initialize the Gemfile.next.lock by copying the content of the
existing Gemfile.lock. This prevents major version jumps when we use
this gem without an initial Gemfile.next.lock.

This commit closes: #24

Author: fbuys

exe/next.sh

@@ -10,6 +10,13 @@ STRING
   mv Gemfile.tmp Gemfile
 
   ln -s Gemfile Gemfile.next
+
+  # Initialize the Gemfile.next.lock
+  # Prevents major version jumps when we start without a Gemfile.next.lock
+  if [ -f "Gemfile.lock" ] && [ ! -f "Gemfile.next.lock" ]; then
+    cp Gemfile.lock Gemfile.next.lock
+  fi
+
   echo <<-MESSAGE
 Created Gemfile.next (a symlink to your Gemfile). Your Gemfile has been modified to support dual-booting!