Web.config example Entity Framework 6 & Npgsql.EntityFramework (PostgreSQL)

web.config EF6 Npgsql.EntityFramework example.xml

<?xml version="1.0" encoding="utf-8"?>
<configuration>
	<configSections>
		<!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
		<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Culture=neutral" requirePermission="false" />
	</configSections>
	
	<system.web>
		<compilation debug="true" targetFramework="4.5">
			<assemblies>
				<add assembly="System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
			</assemblies>
		</compilation>
		
		<pages>
			<namespaces>
				<add namespace="System.Web.Mvc" />
				<add namespace="System.Web.Mvc.Html" />
			</namespaces>
		</pages>
	</system.web>
	
	<system.webServer>
		<modules runAllManagedModulesForAllRequests="true" />
	</system.webServer>
	
	<system.data>
		<DbProviderFactories>
			<add name="Npgsql Data Provider"
			     invariant="Npgsql"
			     description ="Data Provider for PostgreSQL"
			     type="Npgsql.NpgsqlFactory, Npgsql" />
		</DbProviderFactories>
	</system.data>
	
	<connectionStrings>
		<add name="Context"
		     connectionString="Server=127.0.0.1;port=5432;Database=test;User Id=test;Password=test1234;"
		     providerName="Npgsql" />
	</connectionStrings>
	
	<entityFramework>
		<providers>
			<provider invariantName="Npgsql"
			          type="Npgsql.NpgsqlServices, Npgsql.EntityFramework" />
		</providers>
	</entityFramework>

</configuration>

I have used the order 1-system.data,2-ConnectionString,3-entityFrameWork and solve my problem which gives message "ArgumentException: The ADO.NET provider with invariant name 'Npgsql' is either not registered in the machine or application config file, or could not be loaded. See the inner exception for details." Thanks