diff --git a/src/SUMMARY.md b/src/SUMMARY.md
index ca3b6da..85c7298 100644
--- a/src/SUMMARY.md
+++ b/src/SUMMARY.md
@@ -12,6 +12,8 @@
   - [Rust](./dev/rust/main.md)
     - [serde](./dev/rust/serde.md)
     - [Testing](./dev/rust/testing.md)
+  - [Ruby](./dev/ruby/main.md)
+    - [arrays](./dev/ruby/arrays.md)
   - [Web](./dev/web/main.md)
     - [front](./dev/web/front/main.md)
       - [babel and babel-preset-stage-2](./dev/web/front/babel-preset-stage-2.md)
diff --git a/src/dev/ruby/arrays.md b/src/dev/ruby/arrays.md
new file mode 100644
index 0000000..cf86b7a
--- /dev/null
+++ b/src/dev/ruby/arrays.md
@@ -0,0 +1,6 @@
+# Check if all array elements are equals
+
+```ruby
+arr = [0, 0, 0, 0, 0, 0, 0]
+puts true if arr.uniq.length == 1
+```
diff --git a/src/dev/ruby/main.md b/src/dev/ruby/main.md
new file mode 100644
index 0000000..99ea45d
--- /dev/null
+++ b/src/dev/ruby/main.md
@@ -0,0 +1 @@
+# Ruby