Add coverage badge

ololobus · ololobus · commit 830cc919612f · 2019-11-28T18:30:34.000+03:00
diff --git a/README.md b/README.md
@@ -1,4 +1,5 @@
 [![Build Status](https://travis-ci.org/postgrespro/pg_query_state.svg?branch=master)](https://travis-ci.org/postgrespro/pg_query_state)
+[![codecov](https://codecov.io/gh/postgrespro/pg_query_state/branch/master/graph/badge.svg)](https://codecov.io/gh/postgrespro/pg_query_state)
 
 # pg\_query\_state
 The `pg_query_state` module provides facility to know the current state of query execution on working backend. To enable this extension you have to patch the latest stable version of PostgreSQL. Different branches are intended for different version numbers of PostgreSQL, e.g., branch _PG9_5_ corresponds to PostgreSQL 9.5.

Original file line number	Diff line number	Diff line change
`@@ -1,4 +1,5 @@`
`1`	`1`	`[![Build Status](https://travis-ci.org/postgrespro/pg_query_state.svg?branch=master)](https://travis-ci.org/postgrespro/pg_query_state)`
	`2`	`+[![codecov](https://codecov.io/gh/postgrespro/pg_query_state/branch/master/graph/badge.svg)](https://codecov.io/gh/postgrespro/pg_query_state)`
`2`	`3`
`3`	`4`	`# pg\_query\_state`
`4`	`5`	The `pg_query_state` module provides facility to know the current state of query execution on working backend. To enable this extension you have to patch the latest stable version of PostgreSQL. Different branches are intended for different version numbers of PostgreSQL, e.g., branch _PG9_5_ corresponds to PostgreSQL 9.5.