diff --git a/.ruby-version b/.ruby-version
new file mode 100644
index 0000000..c043eea
--- /dev/null
+++ b/.ruby-version
@@ -0,0 +1 @@
+2.2.1
diff --git a/Gemfile b/Gemfile
index ae4b309..2065886 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,4 +1,5 @@
 source 'https://rubygems.org'
+ruby '2.2.1'
 
 gem 'sinatra'
 gem 'faraday'