Debian already has 0.8

--- a/Gemfile
+++ b/Gemfile
@@ -81,7 +81,7 @@
 
 # API
 gem 'grape', '~> 1.5', '>= 1.5.2'
-gem 'grape-entity', '~> 0.7.1'
+gem 'grape-entity', '~> 0.8'
 gem 'rack-cors', '~> 1.0', '>= 1.0.6', require: 'rack/cors'
 
 # GraphQL API