on init, connect to AWS and check for the AS group

lib/aws-missing-tools/aws-ha-release/aws-ha-release.rb

@@ -1,2 +1,12 @@
 class AwsHaRelease
+  def initialize(opts)
+    AWS.config(access_key_id: opts[:aws_access_key], secret_access_key: opts[:aws_secret_key], region: opts[:region])
+
+    @as = AWS::AutoScaling.new
+    @group = @as.groups[opts[:as_group_name]]
+
+    if @group.nil?
+      raise ArgumentError, "The Auto Scaling Group named #{opts[:as_group_name]} does not exist in #{opts[:region]}."
+    end
+  end
 end