feat: add read-only support of the meta API (#13)

* Add bases API.

* Implement get tables schema

* Rename GetBase to GetBaseSchema

* Add tests

* Update doc

base.go

@@ -0,0 +1,89 @@
+package airtable
+
+import (
+	"net/url"
+)
+
+// Base type of airtable base.
+type Base struct {
+	ID              string `json:"id"`
+	Name            string `json:"name"`
+	PermissionLevel string `json:"permissionLevel"`
+}
+
+// Base type of airtable bases.
+type Bases struct {
+	Bases  []*Base `json:"bases"`
+	Offset string  `json:"offset,omitempty"`
+}
+
+type Field struct {
+	ID          string `json:"id"`
+	Type        string `json:"type"`
+	Name        string `json:"name"`
+	Description string `json:"description"`
+}
+type View struct {
+	ID   string `json:"id"`
+	Type string `json:"type"`
+	Name string `json:"name"`
+}
+
+type TableSchema struct {
+	ID             string   `json:"id"`
+	PrimaryFieldID string   `json:"primaryFieldId"`
+	Name           string   `json:"name"`
+	Description    string   `json:"description"`
+	Fields         []*Field `json:"fields"`
+	Views          []*View  `json:"views"`
+}
+
+type Tables struct {
+	Tables []*TableSchema `json:"tables"`
+}
+
+// GetBasesWithParams get bases with url values params
+// https://airtable.com/developers/web/api/list-bases
+func (at *Client) GetBasesWithParams(params url.Values) (*Bases, error) {
+	bases := new(Bases)
+
+	err := at.get("meta", "bases", "", params, bases)
+	if err != nil {
+		return nil, err
+	}
+
+	return bases, nil
+}
+
+// Table represents table object.
+type BaseConfig struct {
+	client *Client
+	dbId   string
+	params url.Values
+}
+
+// GetBase return Base object.
+func (c *Client) GetBaseSchema(dbId string) *BaseConfig {
+	return &BaseConfig{
+		client: c,
+		dbId:   dbId,
+	}
+}
+
+// Do send the prepared
+func (b *BaseConfig) Do() (*Tables, error) {
+	return b.GetTablesWithParams()
+}
+
+// GetTablesWithParams get tables from a base with url values params
+// https://airtable.com/developers/web/api/get-base-schema
+func (b *BaseConfig) GetTablesWithParams() (*Tables, error) {
+	tables := new(Tables)
+
+	err := b.client.get("meta/bases", b.dbId, "tables", nil, tables)
+	if err != nil {
+		return nil, err
+	}
+
+	return tables, nil
+}