Add database integration package changelog entry
## ChangeLog
+### New Features
+
+* Introduce support for databases using
+[database/sql](https://golang.org/pkg/database/sql/). This new functionality
+allows you to instrument MySQL, PostgreSQL, and SQLite calls without manually
+creating
+[DatastoreSegment](https://godoc.org/github.com/newrelic/go-agent#DatastoreSegment)s.
+
+| Database Library Supported | Integration Package |
+| ------------- | ------------- |
+| [go-sql-driver/mysql](https://github.com/go-sql-driver/mysql) | [_integrations/nrmysql](https://godoc.org/github.com/newrelic/go-agent/_integrations/nrmysql) |
+| [lib/pq](https://github.com/lib/pq) | [_integrations/nrpq](https://godoc.org/github.com/newrelic/go-agent/_integrations/nrpq) |
+| [mattn/go-sqlite3](https://github.com/mattn/go-sqlite3) | [_integrations/nrsqlite3](https://godoc.org/github.com/newrelic/go-agent/_integrations/nrsqlite3) |
+
+Using these database integration packages is easy! First replace the driver
+with our integration version:
+
+```go
+import (
+ // import our integration package in place of "github.com/go-sql-driver/mysql"
+ _ "github.com/newrelic/go-agent/_integrations/nrmysql"
+)
+
+func main() {
+ // open "nrmysql" in place of "mysql"
+ db, err := sql.Open("nrmysql", "user@unix(/path/to/socket)/dbname")
+}
+```
+
+Second, use the `ExecContext`, `QueryContext`, and `QueryRowContext` methods of
+[sql.DB](https://golang.org/pkg/database/sql/#DB),
+[sql.Conn](https://golang.org/pkg/database/sql/#Conn),
+[sql.Tx](https://golang.org/pkg/database/sql/#Tx), and
+[sql.Stmt](https://golang.org/pkg/database/sql/#Stmt) and provide a
+transaction-containing context. Calls to `Exec`, `Query`, and `QueryRow` do not
+get instrumented.
+
+```go
+ctx := newrelic.NewContext(context.Background(), txn)
+row := db.QueryRowContext(ctx, "SELECT count(*) from tables")
+```
+
+If you are using a [database/sql](https://golang.org/pkg/database/sql/) database
+not listed above, you can write your own instrumentation for it using
+[InstrumentConnector](https://godoc.org/github.com/newrelic/go-agent#InstrumentConnector),
+[InstrumentDriver](https://godoc.org/github.com/newrelic/go-agent#InstrumentDriver),
+and
+[DriverSegmentBuilder](https://godoc.org/github.com/newrelic/go-agent#DriverSegmentBuilder).
+The integration packages act as examples of how to do this.
+
## 2.7.0
### New Features
