Update README and create CHANGELOG to reflect new connection parameters

Author: nornagon

CHANGELOG.md

@@ -0,0 +1,20 @@
+## 3.0.0
+
+Thanks to @billwashere, we upgraded to a more modern version of `pg` (4.5.1 ->
+7.4.1), which means that the way the database information is provided has
+changed. Previously, you could pass a URL to sharedb-postgres, like:
+
+```js
+const db = require('sharedb-postgres')('postgres://localhost/mydb');
+```
+
+This is no longer supported, and you must instead pass a config object:
+
+```js
+const db = require('sharedb-postgres')({host: 'localhost', database: 'mydb'});
+```
+
+See the [node-postgres](https://node-postgres.com/features/connecting)
+documentation for more details about what can be passed in the config object.
+Additionally, if no object is provided, `pg` will use the same environment
+variables as `libpq` (`PGUSER`, `PGHOST` and so on).

README.md

@@ -16,10 +16,15 @@ To instantiate a sharedb-postgres wrapper, invoke the module and pass in your
 PostgreSQL configuration as an argument. For example:
 
 ```js
-var db = require('sharedb-postgres')('postgres://localhost/mydb');
+var db = require('sharedb-postgres')({host: 'localhost', database: 'mydb'});
 var backend = require('sharedb')({db: db})
 ```
 
 ## Error codes
 
 PostgreSQL errors are passed back directly.
+
+## Changelog
+
+Note that version 3.0.0 introduces breaking changes in how you specify
+connection parameters. See the [changelog](CHANGELOG.md) for more info.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "sharedb-postgres",
-  "version": "2.0.0",
+  "version": "3.0.0",
   "description": "PostgreSQL adapter for ShareDB",
   "main": "index.js",
   "scripts": {
@@ -14,4 +14,4 @@
     "pg": "^7.4.1",
     "sharedb": "^1.0.0-beta.7"
   }
-}
+}