Fixes PostgresSQL connection problems.

This commit fixes the following connection problems:
* Pools should now properly release themselves always
* You can now set a "TestOnBorrow"-like functionality with
  config.pool.reapInterval).
* Heroku should be able to properly send the correct DB credentials.

lib/dialects/postgres/connector-manager.js

@@ -21,6 +21,7 @@ module.exports = (function() {
     if (this.pooling) {
       this.pg.defaults.poolSize           = this.config.pool.maxConnections
       this.pg.defaults.poolIdleTimeout    = this.config.pool.maxIdleTime
+      this.pg.defaults.reapIntervalMillis = this.config.pool.reapInterval || 1000
     }
 
     this.disconnectTimeoutId = null
@@ -57,9 +58,9 @@ module.exports = (function() {
       })
       .on('success', function(done) {
         var query = new Query(self.client, self.sequelize, callee, options || {})
-        done = done || null
 
-        return query.run(sql, done)
+        return query.run(sql)
+          .complete(function(err) { done && done(err) })
           .success(function(results) { self.endQuery.call(self) })
           .error(function(err) { self.endQuery.call(self) })
           .proxy(emitter)
@@ -113,6 +114,7 @@ module.exports = (function() {
           emitter.emit('success', done)
         })
       } else {
+        done && done()
         self.client = null
         emitter.emit('success', done)
       }
@@ -120,8 +122,7 @@ module.exports = (function() {
 
     if (this.pooling) {
       // acquire client from pool
-      this.poolIdentifier = this.pg.pools.getOrCreate(uri)
-      this.poolIdentifier.connect(connectCallback)
+      this.pg.connect(uri, connectCallback)
     } else {
       if (!!this.client && this.client.readyForQuery === true) {
         connectCallback(null, this.client)

lib/dialects/postgres/query.js

@@ -18,7 +18,7 @@ module.exports = (function() {
   }
   Utils.inherit(Query, AbstractQuery)
 
-  Query.prototype.run = function(sql, done) {
+  Query.prototype.run = function(sql) {
     this.sql = sql
     var self = this
 
@@ -40,7 +40,6 @@ module.exports = (function() {
     }.bind(this))
 
     query.on('end', function() {
-      done && done()
       this.emit('sql', this.sql)
 
       if (receivedError) {