Update README.md

Author: dedok

README.md

@@ -0,0 +1,101 @@
+# nginx_upstream_module
+Tarantool NginX upstream module (JSON API, websockets, load balancing)
+
+  Key features:
+  * United nginx features and tarantool features over HTTP(S).
+  * Call tarantool methods via json rpc.
+
+  About tarantool: http://tarantool.org
+  
+  About upstream: http://nginx.org/en/docs/http/ngx_http_upstream_module.html#upstream
+
+## Protocol
+
+  Module expectes json posted over HTTP POST in request body.
+
+### Input JSON form
+
+    { "method": METHOD_NAME, "params":[TNT_METHOD, arg0 ... argN], "id": ID }
+
+    "method"
+
+      A String containing the name of the method to be invoked,
+      i.e. Tarantool "call", "eval", etc.
+
+      Notice. Only tarantool "call" method is supported.
+
+    "params"
+
+      Here is a Structured array, that MUST hold the TNT_METHOD name as first element before all of the rest elements.
+      These elements are arguments of TNT_METHOD.
+
+    "id"
+      An identifier established by the Client MUST contain an unsigned Number not
+      greater than unsigned int.
+
+    These are required fields.
+
+### Output JSON form
+
+    { "result": JSON_RESULT_OBJECT, "id" ID, "error": { "message": STR } }
+
+    "result"
+
+      Tarantool executing result as json object/array etc.
+      MAY be null or undefined.
+
+    "id"
+
+      Request id is returned back.
+      MAY be null or undefined in case of internal error.
+
+
+    "error"
+
+      Here is a Structured object which contains internal error message.
+      This field exists only if internal error occured, for instance "too large
+      request", "input json parse error", etc.
+
+      If this field exists input message did not pass to Tarantool backend.
+
+      See "message" field for details.
+
+
+## Compilation and install
+
+### Build from the sources
+
+    $ cd REPO_ROOT
+    $ git submodule init
+    $ git submodule update
+    $ git clone https://github.com/nginx/nginx.git nginx
+    $ make build-all # build-all-debug i.e. debug version
+
+### Build module via nginx 'configure'
+
+  Requirements (for details see REPO_ROOT/Makefile)
+
+    libyajl >= 2.0(https://lloyd.github.io/yajl/)
+    libtp (https://github.com/tarantool/tarantool-c)
+
+    $ ./configure --add-module=REPO_ROOT && make
+
+## Configuration
+
+```nginx
+
+    upstream backend {
+        server 127.0.0.1:9999;
+        # ...
+    }
+
+    server {
+      location = /tnt {
+        tnt_pass backend;
+      }
+    }
+
+```
+
+Please report bugs at https://github.com/tarantool/nginx_upstream_module/issues
+We also warmly welcome your feedback in the discussion mailing list, tarantool@googlegroups.com.