PostgreSQL prep

Update of vendored SQL libs and refactoring of store provider layer.

vendor/github.com/lib/pq/connector.go

@@ -0,0 +1,43 @@
+// +build go1.10
+
+package pq
+
+import (
+	"context"
+	"database/sql/driver"
+)
+
+// Connector represents a fixed configuration for the pq driver with a given
+// name. Connector satisfies the database/sql/driver Connector interface and
+// can be used to create any number of DB Conn's via the database/sql OpenDB
+// function.
+//
+// See https://golang.org/pkg/database/sql/driver/#Connector.
+// See https://golang.org/pkg/database/sql/#OpenDB.
+type connector struct {
+	name string
+}
+
+// Connect returns a connection to the database using the fixed configuration
+// of this Connector. Context is not used.
+func (c *connector) Connect(_ context.Context) (driver.Conn, error) {
+	return (&Driver{}).Open(c.name)
+}
+
+// Driver returnst the underlying driver of this Connector.
+func (c *connector) Driver() driver.Driver {
+	return &Driver{}
+}
+
+var _ driver.Connector = &connector{}
+
+// NewConnector returns a connector for the pq driver in a fixed configuration
+// with the given name. The returned connector can be used to create any number
+// of equivalent Conn's. The returned connector is intended to be used with
+// database/sql.OpenDB.
+//
+// See https://golang.org/pkg/database/sql/driver/#Connector.
+// See https://golang.org/pkg/database/sql/#OpenDB.
+func NewConnector(name string) (driver.Connector, error) {
+	return &connector{name: name}, nil
+}