use "postgres" as username during initdb PostgresApp#275

This change uses the user name "postgres" when calling initdb. This is the de facto standard used by other PostgreSQL distributions, and should make restoring from dumps more usable.

To keep Postgres.app as simple to use, Postgres.app also creates a super user with the same name as the current system user, and creates a database with the same name. This makes sure that typing "psql" in terminal is all that's needed to connect to Postgres.app

Postgres/PostgresServer.m

@@ -170,6 +170,12 @@ - (void)startWithCompletionHandler:(PostgresServerControlCompletionHandler)compl
 				return;
 			}
 
+			BOOL createdUser = [self createUserWithError:&error];
+			if (!createdUser) {
+				if (completionBlock) dispatch_async(dispatch_get_main_queue(), ^{ completionBlock(NO, error); });
+				return;
+			}
+
 			BOOL createdUserDatabase = [self createUserDatabaseWithError:&error];
 			if (completionBlock) dispatch_async(dispatch_get_main_queue(), ^{ completionBlock(createdUserDatabase, error); });
 		}
@@ -301,7 +307,8 @@ -(BOOL)initDatabaseWithError:(NSError**)error {
 	initdbTask.launchPath = [self.binPath stringByAppendingPathComponent:@"initdb"];
 	initdbTask.arguments = @[
 		/* data directory */ @"-D", self.varPath,
-		/* encoding       */ @"-EUTF-8",
+		/* superuser name */ @"-U", @"postgres",
+		/* encoding       */ @"--encoding=UTF-8",
 		/* locale         */ @"--locale=en_US.UTF-8"
 	];
 	initdbTask.standardError = [[NSPipe alloc] init];
@@ -319,6 +326,34 @@ -(BOOL)initDatabaseWithError:(NSError**)error {
 	return initdbTask.terminationStatus == 0;
 }
 
+-(BOOL)createUserWithError:(NSError**)error {
+	NSTask *task = [[NSTask alloc] init];
+	task.launchPath = [self.binPath stringByAppendingPathComponent:@"createuser"];
+	task.arguments = @[
+					   @"-U", @"postgres",
+					   @"-p", @(self.port).stringValue,
+					   @"--superuser",
+					   NSUserName()
+	];
+	task.standardError = [[NSPipe alloc] init];
+	[task launch];
+	NSString *taskError = [[NSString alloc] initWithData:[[task.standardError fileHandleForReading] readDataToEndOfFile] encoding:NSUTF8StringEncoding];
+	[task waitUntilExit];
+
+	if (task.terminationStatus != 0 && error) {
+		NSMutableDictionary *errorUserInfo = [[NSMutableDictionary alloc] init];
+		errorUserInfo[NSLocalizedDescriptionKey] = NSLocalizedString(@"Could not create default user.",nil);
+		errorUserInfo[NSLocalizedRecoverySuggestionErrorKey] = taskError;
+		errorUserInfo[NSLocalizedRecoveryOptionsErrorKey] = @[@"OK", @"Open Server Log"];
+		errorUserInfo[NSRecoveryAttempterErrorKey] = [[RecoveryAttempter alloc] init];
+		errorUserInfo[@"ServerLogRecoveryOptionIndex"] = @1;
+		errorUserInfo[@"ServerLogPath"] = self.logfilePath;
+		*error = [NSError errorWithDomain:@"com.postgresapp.Postgres.createuser" code:task.terminationStatus userInfo:errorUserInfo];
+	}
+
+	return task.terminationStatus == 0;
+}
+
 -(BOOL)createUserDatabaseWithError:(NSError**)error {
 	NSTask *task = [[NSTask alloc] init];
 	task.launchPath = [self.binPath stringByAppendingPathComponent:@"createdb"];