1. Generate self signed client-key and client pem and server-cert and server.pem files
openssl genrsa 2048 > ca-key.pem
openssl req -sha1 -new -x509 -nodes -days 3650 -key ca-key.pem > ca-cert.pem
openssl req -sha1 -newkey rsa:2048 -days 730 -nodes -keyout server-key.pem > server-req.pem
openssl x509 -sha1 -req -in server-req.pem -days 730  -CA ca-cert.pem -CAkey ca-key.pem -set_serial 01 > server-cert.pem
openssl rsa -in server-key.pem -out server-key.pem
openssl req -sha1 -newkey rsa:2048 -days 730 -nodes -keyout client-key.pem > client-req.pem
openssl x509 -sha1 -req -in client-req.pem -days 730 -CA ca-cert.pem -CAkey ca-key.pem -set_serial 01 > client-cert.pem
openssl rsa -in client-key.pem -out client-key.pem

2. copy all the pem files in mysql path
sudo cp ca-cert.pem server-cert.pem server-key.pem client-cert.pem client-key.pem /etc/mysql

3.add this under [client] section of my.conf section:
ssl-ca=/etc/mysql/ca-cert.pem
ssl-cert=/etc/mysql/client-cert.pem
ssl-key=/etc/mysql/client-key.pem

4.Uncomment the following lines
ssl=1
  ssl-ca=/etc/mysql/ca-cert.pem
  ssl-cert=/etc/mysql/server-cert.pem
 ssl-key=/etc/mysql/server-key.pem

5.restart mysql
sudo service mysql restart


6.in config/database.yml
in default write
sslkey: /etc/mysql/client-key.pem
  sslcert: /etc/mysql/client-cert.pem
  sslca: /etc/mysql/ca-cert.pem
  sslcapath: /etc/mysql

GRANT ALL PRIVILEGES TO 'root'@'%' REQUIRE SSL;
UPDATE mysql.user SET password=PASSWORD('root')  WHERE  User='root' AND Host='%';
FLUSH PRIVILEGES;