How to: Writing Config Files
At times you may want to store all configuration modifications made during run
time.

```go
// Writes current config to the path set by `AddConfigPath` and `SetConfigName`
viper.WriteConfig()
viper.SafeWriteConfig() // Like the above, but will error if the config file exists

// Writes current config to a specific place
viper.WriteConfigAs("/path/to/my/.config")

// Will error since it has already been written
viper.SafeWriteConfigAs("/path/to/my/.config")

viper.SafeWriteConfigAs("/path/to/my/.other_config")
```

As a rule of the thumb, methods prefixed with `Safe` won't overwrite any
existing file, while other methods will.