Add csv extractor

docs/Extractors/Csv.md

@@ -0,0 +1,31 @@
+# CSV Extractor
+
+The csv extractor can be used to get data from comma separated files with or without a header row.
+
+## Options
+
+| Name | Type | Default | Description |
+| ---- |----- | ------- | ----------- |
+| columns | array | null | Columns that will be extracted. |
+| delimiter | string | , | Field delimiter (one character only). |
+| enclosure | string | | Field enclosure character (one character only). |
+
+
+## Usage
+
+Default options:
+```php
+$etl->extract('csv', 'path/to/file.csv');
+```
+
+Custom options:
+```php
+$options = [
+    'columns' => [
+        'id' => 1, // Index of the column in the csv file (The first column is 1).
+        'name' => 2
+    ]
+];
+
+$etl->extract('csv', 'path/to/file.csv', $options);
+```

docs/Extractors/README.md

@@ -1,3 +1,4 @@
 # Extractors
 
 * [Collection](Collection.md)
+* [CSV](Csv.md)

docs/README.md

@@ -2,3 +2,4 @@
 * [Getting Started](GettingStarted.md)
 * [Extractors](Extractors/README.md)
     * [Collection](Extractors/Collection.md)
+    * [CSV](Extractors/Csv.md)