Merge pull request #446 from designerror/patch-1

Update README.md
travis-ci · Apr 8, 2020 · fc69722 · fc69722
2 parents 9f5cf25 + e9b71af
commit fc69722
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/README.md b/README.md
@@ -2065,7 +2065,7 @@ Ubuntu:
     $ sudo apt-get install python-software-properties
     $ sudo apt-add-repository ppa:brightbox/ruby-ng
     $ sudo apt-get update
-    $ sudo apt-get install ruby2.1 ruby-switch
+    $ sudo apt-get install ruby2.1 ruby2.1-dev ruby-switch
     $ sudo ruby-switch --set ruby2.1
 
 Fedora: