generate debug key hash for facebook code example

Example 1: generate sha1 key for facebook login android

keytool -exportcert -alias <aliasName> -keystore <keystoreFilePath> | openssl sha1 -binary | openssl base64

Example 2: generate sha1 key for facebook login android

keytool -exportcert -alias androiddebugkey -keystore debug.keystore | openssl sha1 -binary | openssl base64