How to fix metasploit failed to connect to the database

This tutorial describes How to fix metasploit failed to connect to the database in Kali Linux2.0 Sana .

My scenario:- Today i did some experimental with Kali Linux Sana. I tired to connect metasploit database with postgresql it failed to connect database these is the error i got during experimental.
Error:-
root@kali:~# service postgresql start
root@kali:~# service postgresql status
● postgresql.service - PostgreSQL RDBMS
   Loaded: loaded (/lib/systemd/system/postgresql.service; disabled)
   Active: active (exited) since Sun 2016-09-11 16:44:35 IST; 48min ago
  Process: 6448 ExecStart=/bin/true (code=exited, status=0/SUCCESS)
 Main PID: 6448 (code=exited, status=0/SUCCESS)
   CGroup: /system.slice/postgresql.service
root@kali:~# service metasploit start
Failed to start metasploit.service: Unit metasploit.service failed to load: No such file or directory.


  root@kali:~# msfconsole
                                                  ole.../
# cowsay++
 ____________
< metasploit >
 ------------
       \   ,__,
        \  (oo)____
           (__)    )\
              ||--|| *


Save 45% of your time on large engagements with Metasploit Pro
Learn more on http://rapid7.com/metasploit

       =[ metasploit v4.11.4-2015071403                   ]
+ -- --=[ 1467 exploits - 840 auxiliary - 232 post        ]
+ -- --=[ 432 payloads - 37 encoders - 8 nops             ]
+ -- --=[ Free Metasploit Pro trial: http://r-7.co/trymsp ]

msf > db_status
[*] postgresql selected, no connection


Solution:-
Here is the solution to fix metasploit failed to connect to the database.
root@kali:~# /usr/bin/msfconsole
msf > msfdb init
[*] exec: msfdb init
msf > msfconsole
[*] exec: msfconsole
msf > db_status
[*] postgresql connected to msf
              [OR]
root@kali:~# /usr/bin/msfconsole start
msf > db_status
[*] postgresql connected to msf

I hope you this information is useful for you. Please forgive any typos or incomplete sentences.