improve README.md, add PyPi badge

Author: funbringer

README.md

@@ -1,67 +1,87 @@
+[![PyPI version](https://badge.fury.io/py/testgres.svg)](https://badge.fury.io/py/testgres)
+
 # testgres
 
-Postgres testing utility
+PostgreSQL testing utility.
+
 
 ## Installation
 
-To install `testgres` run:
+To install `testgres`, run:
 
 ```
 pip install testgres
 ```
 
-At current state it only works with Python 2.*
+We encourage you to use `virtualenv` for your testing environment. Currently `testgres` works only with Python 2.x, but this is going to change soon.
 
-## Usage
 
+## Usage
 
-> Node: by default testgres runs `initdb`, `pg_ctl`, `psql` commands from the `$PATH`. To specify custom postgres installation set environment variable `$PG_CONFIG` and point it to pg_config executable: `export PG_CONFIG=/path/to/pg_config`
+> Note: by default testgres runs `initdb`, `pg_ctl`, `psql` provided by `$PATH`. To specify a custom postgres installation, set the environment variable `$PG_CONFIG` pointing to the `pg_config` executable: `export PG_CONFIG=/path/to/pg_config`.
 
-Here is an example of how you can use `testgres`.
+Here is an example of what you can do with `testgres`:
 
 ```python
-from testgres import get_new_node
+import testgres
 
 try:
-    node = get_new_node('master')
-    node.init()
-    node.start()
-    stdout = node.safe_psql('postgres', 'SELECT 1')
-    print stdout
+    node = testgres.get_new_node('test').init().start()
+    print node.safe_psql('postgres', 'SELECT 1')
     node.stop()
 except ClusterException, e:
+    print e
+finally:
     node.cleanup()
 ```
 
 Let's walk through the code. First you create new node:
 
 ```python
-node = get_new_node('master')
+node = testgres.get_new_node('master')
 ```
 
-`master` here is a node's name, not the database's name. The name matters if you're testing replication. Function `get_new_node()` only creates directory structure in `/tmp` for cluster. Next line:
+`master` is a node's name, not the database's name. The name matters if you're testing something like replication. Function `get_new_node()` only creates directory structure in `/tmp` for cluster. After that, we have to initialize the PostgreSQL cluster:
 
 ```python
 node.init()
 ```
 
-initializes cluster. On low level it runs `initdb` command and adds some basic configuration to `postgresql.conf` and `pg_hba.conf` files. Function `init()` accepts optional parameter `allows_streaming` which configures cluster for streaming replication (default is `False`).
+This function runs `initdb` command and adds some basic configuration to `postgresql.conf` and `pg_hba.conf` files. Function `init()` accepts optional parameter `allows_streaming` which configures cluster for streaming replication (default is `False`).
 Now we are ready to start:
 
 ```python
 node.start()
 ```
 
-After this you are able to run queries over the cluster. There are three functions to do that:
+Finally our temporary cluster is able to process queries. There are four ways to run them:
 
-* `node.psql(database, query)` - runs query via `psql` command and returns tuple (error code, stdout, stderr)
-* `node.safe_psql(database, query)` - the same as `psql()` except that it returns only `stdout`. If error occures during the execution then it will throw an exception;
-* `node.execute(database, query)` - connects with postgresql server using `psycopg2` or `pg8000` library (depends on which is installed in your system) and returns two-dimensional array with data.
+* `node.psql(database, query)` - runs query via `psql` command and returns tuple `(error code, stdout, stderr)`
+* `node.safe_psql(database, query)` - same as `psql()` except that it returns only `stdout`. If an error occures during the execution, an exception will be thrown.
+* `node.execute(database, query)` - connects to postgresql server using `psycopg2` or `pg8000` library (depends on which is installed in your system) and returns two-dimensional array with data.
+* `node.connect(database='postgres')` - returns connection wrapper (`NodeConnection`) capable of running several queries within a single transaction.
 
-To stop server run:
+The last one is the most powerful: you can use `begin(isolation_level)`, `commit()` and `rollback()`:
+```python
+with node.connect() as con:
+    con.begin('serializable')
+    print con.execute('select %s', 1)
+    con.rollback()
+```
+
+To stop the server, run:
 
 ```python
 node.stop()
 ```
 
+It is essential to clean everything up, so make sure to call `node.cleanup()` once you've finished all of your tests.
+
 Please see `testgres/tests` directory for replication configuration example.
+> Note: you could take a look at [`pg_pathman`](https://github.com/postgrespro/pg_pathman) to get an idea of `testgres`' capabilities.
+
+
+## Authors
+
+Ildar Musin <i.musin@postgrespro.ru> Postgres Professional Ltd., Russia		
+Dmitry Ivanov <d.ivanov@postgrespro.ru> Postgres Professional Ltd., Russia