Merge pull request #131 from appbaseio/ugo/jsonl-adaptor/19-12-2018

Add doc for jsonl adaptor

docs/importer/adaptors/jsonl.md

+JSONL adaptor
+=============
+
+The jsonl adaptor reads the data from jsonl file.
+
+Here is how the configuration looks like:
+
+    src_type=jsonl
+    src_uri=/full/path/to/file.json
+    typename=typename
+
+    dest_type=elasticsearch
+    dest_uri=appname
+
+The `file.json` should contain JSON lines text format, also called newline-delimited JSON.
+For more information on jsonl format checkout this [link](http://jsonlines.org/).
+
+Example:
+
+    {"name": "Gilbert", "wins": [["straight", "7♣"], ["one pair", "10♥"]]}
+    {"name": "Alexa", "wins": [["two pair", "4♠"], ["two pair", "9♠"]]}
+    {"name": "May", "wins": []}
+    {"name": "Deloise", "wins": [["three of a kind", "5♣"]]}
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