Add support for duration and many upgrades

• Many upgrades to dependent libraries and go version
• Adds support for duration type for datasets

v0.2.4: Merge pull request #27 from geckoboard/feature-upgrade-lib-mysql

MySQL library update to support new authenication mechanism in MySQL 8.1+

v0.3.0.alpha: Upgrade mysql go library to support mysql 8.1

This is because the default password plugin has changed
to sha2 plugin meaning the old authentication with mysql 8.1
wasn't compatible

Bugfix for unique by keys not matching field keys

This release fixes a small but important bug with unique by as raised by @SirRawlins in issue #22

This will now properly support specifying the unique by in the same format as your field name. Which under the hood we will convert correctly just like the field name is.

 - name: subscriptions.all
    update_type: append
    sql: SELECT 1 FROM Y
    fields:
      - type: datetime
        name: Subscribed At
    unique_by:
      - Subscribed At

Tiny bugfix and error message improvments

• Improves the errors messages brought to us by @bennewell
• Validates that we have at least one dataset before continuing. (This will help with any indentation issues or mis-spelling)
• Uses db.Ping() to check the connection before continuing.
  This helps identify database connection issues early on instead of trying to make SQL query and it failing.

Fix invalid empty payload to Geckoboard

This minor release fixes sending empty payloads for dataset type Replace - when your SQL result set contains no data - we was sending an invalid payload this release fixes that.

Adds Microsoft SQL Server support

Adds basic odbc connection support for Microsoft SQL Server. Driver named mssql

File descriptor leak bugfix

This fixes a file descriptor leak for long running sql-dataset instances, where by we was incorrectly opening new connection for every sql query, but never closing any.

This changes that so that we only sql.Open once in main and let the sql/database package handle connection pools. With a max limit of 5.

Basic odbc connection support for MSSQL

Supports driver named driver: mssql

---
geckoboard_api_key: ''
database:
 driver: mssql
 host: localhost
 username: sa
 password: xxxx
 name: testdb
 tls_config: (optional)
  ca_file: "path/cert.pem"
  ssl_mode: "true"
refresh_time_sec: 10
datasets:
 - name: 'builds.count'
   update_type: replace
   sql: SELECT count(*) from builds
   fields:
     - type: number
       name: count

Support environment variables in the config

v0.1.1

Update readme with new release