README.md in embulk-output-bigquery-0.1.11 vs README.md in embulk-output-bigquery-0.2.0

@@ -26,10 +26,11 @@
 
 #### Original options
 
 | name                      | type        | required?  | default      | description            |  
 |:--------------------------|:------------|:-----------|:-------------|:-----------------------|
+|  mode                     | string      | optional   | append       | [See below](#mode)     |
 |  auth_method              | string      | optional   | "private_key"  | `private_key` , `json_key` or `compute_engine`
 |  service_account_email    | string      | required when auth_method is private_key  |   | Your Google service account email
 |  p12_keyfile              | string      | required when auth_method is private_key   |   | Fullpath of private key in P12(PKCS12) format |
 |  json_keyfile             | string      | required when auth_method is json_key     |   | Fullpath of json key |
 |  sequence_format          | string      | optional   | %03d.%02d      |  |
@@ -77,9 +78,39 @@
     type: csv
     header_line: false
   encoders:
   - {type: gzip}
 ```
+
+### mode
+
+4 modes are provided.
+
+#### append
+
+default. When append mode, plugin will insert data into existing table.
+
+#### replace
+
+1. Load to temporary table.
+2. Copy temporary table to destination table. (WRITE_TRUNCATE)
+
+```is_skip_job_result_check``` must be false when replace mode
+
+#### replace_backup
+
+1. Load to temporary table.
+2. Copy destination table to backup table. (table_name_old)
+3. Copy temporary table to destination table. (WRITE_TRUNCATE)
+
+```is_skip_job_result_check``` must be false when replace_backup mode.
+
+#### delete_in_advance
+
+1. Delete destination table, if it exists.
+2. Load to destination table.
+
+```auto_create_table``` must be true when delete_in_advance mode.
 
 ### Authentication
 
 There are three methods supported to fetch access token for the service account.