diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
new file mode 100644
index 0000000..1dcbdbd
--- /dev/null
+++ b/.github/workflows/main.yml
@@ -0,0 +1,35 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        luaVersion: ["5.4"]
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - uses: leafo/gh-actions-lua@v9
+        with:
+          luaVersion: ${{ matrix.luaVersion }}
+
+      - uses: leafo/gh-actions-luarocks@v4
+
+      - name: Install dependencies
+        run: luarocks install simple_test
+
+      - name: Run unit tests
+        run: |
+          LUA_PATH="./src/?.lua;./src/?/init.lua;;$(luarocks path --lr-path)" lua test.lua
diff --git a/README.md b/README.md
index 47b1604..0f4813b 100644
--- a/README.md
+++ b/README.md
@@ -2,9 +2,6 @@
 A small library with useful methods to handle Lua's table when it's working like an Array.<br>
 For docs, see: https://evandrolg.github.io/array.lua/
 
-[![Build
-Status](https://travis-ci.org/EvandroLG/array.lua.svg?branch=master)](https://travis-ci.org/EvandroLG/array.lua)
-
 ## Installation
 To install array, run:
 ```sh
diff --git a/src/array/init.lua b/src/array/init.lua
index 0c843f8..210c5bd 100644
--- a/src/array/init.lua
+++ b/src/array/init.lua
@@ -3,7 +3,7 @@ local utils = require('array.utils')
 local array
 
 array = {
-  __VERSION = '1.3.4',
+  __VERSION = '1.3.6',
   __DESCRIPTION = "A small library with useful methods to handle Lua's table when it's working like an Array",
   __LICENSE = [[
     The MIT License (MIT)
@@ -426,15 +426,19 @@ array = {
     return output
   end,
 
-  -- Create a new table with the sub-table elements concatenated into it
-  -- @param obj {table}
+  -- Create a new table with the sub-table elements concatenated into it up to the specific depth
+  -- @param obj {table, depth}
   -- @return {table}
-  flat = function(obj)
+  flat = function(obj, depth)
+    if depth == nil then
+      depth = 1 / 0 -- Infinity
+    end
+    
     return array.reduce(obj, function(acc, item)
-      if array.is_array(item) then
+      if array.is_array(item) and depth > 0 then
         return array.concat(
           acc,
-          array.flat(item)
+          array.flat(item, depth - 1)
         )
       else
         table.insert(acc, item)
@@ -637,6 +641,31 @@ array = {
     end
 
     return output
+  end,
+
+  -- Returns a new array-like table by applying a given callback to each element of the table, and then flattening the result by one level
+  -- @param obj {table}
+  -- @param callback {function}
+  -- @return {table}
+  flat_map = function(obj, callback)
+    utils.raises_error(array, obj, 'flat_map')
+    local mapped = array.map(obj, callback)
+
+    return array.flat(mapped)
+  end,
+
+  -- Creates a new table composed of keys generated from the results of running each element of the given table through the given callback
+  -- @param obj {table}
+  -- @param callback {function}
+  -- @return {table}
+  key_by = function(obj, callback)
+    utils.raises_error(array, obj, 'key_by')
+
+    return array.reduce(obj, function(accumulator, current)
+      local key = callback(current)
+      accumulator[key] = current
+      return accumulator
+    end, {})
   end
 }
 
diff --git a/test.lua b/test.lua
index 03f2c55..e5b5a3f 100644
--- a/test.lua
+++ b/test.lua
@@ -2,7 +2,7 @@ local test = require 'simple_test'
 local array = require 'array'
 
 test('meta infos', function(a)
-  a.equal(array.__VERSION, '1.3.4')
+  a.equal(array.__VERSION, '1.3.6')
   a.equal(array.__DESCRIPTION,
   "A small library with useful methods to handle Lua's table when it's working like an Array")
 end)
@@ -259,6 +259,16 @@ test('flat', function(a)
     array.flat({ 'a', 'b', 'c', { 'd', 'e', 'f', { 'g', 'h' } }, { 'i' }, 'j' }),
     { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j' }
   )
+
+  a.deep_equal(
+    array.flat({ 'a', 'b', 'c', { 'd', 'e', 'f', { 'g', 'h' } }, { 'i' }, 'j' }, 1),
+    { 'a', 'b', 'c', 'd', 'e', 'f', { 'g', 'h' }, 'i', 'j' }
+  )
+
+  a.deep_equal(
+    array.flat({ 'a', 'b', 'c', { 'd', 'e', { 'f', { 'g', 'h' } } }, { 'i' }, 'j' }, 2),
+    { 'a', 'b', 'c', 'd', 'e', 'f', { 'g', 'h' }, 'i', 'j' }
+  )
 end)
 
 test('fill', function(a)
@@ -415,3 +425,24 @@ test('chunk', function(a)
     }
   )
 end)
+
+test('flat_map', function(a)
+  a.deep_equal(
+    array.flat_map({ 1, 2, 3 }, function(value)
+      return { value, value * 2 }
+    end),
+    { 1, 2, 2, 4, 3, 6 }
+  )
+end)
+
+test('key_by', function(a)
+  a.deep_equal(
+    array.key_by({ { id = 1, name = 'lua' }, { id = 2, name = 'javascript' } }, function(item)
+      return item.id
+    end),
+    {
+      [1] = { id = 1, name = 'lua' },
+      [2] = { id = 2, name = 'javascript' }
+    }
+  ) 
+end)