Issues to be fixed:
* There is no possibility to change the drunkpic for both admin and user. When we upload a custom drunkpic - the image doesn't save into the /ow_static/plugins/drunkmeter/images/ folder and appears as broken;
* When we add a new drink, the image doesn't save either;
* We can add nonnumeric value into the 'Price' field;
* No confirmation message when new drink is added;
* User can send the paid drink even if they have no credits;
* If a 'User Credits' plugin is not installed, the price for drink should not be visible.
* Rename the 'Add settings' tab to the 'Add drink' or move the 'Add drink' form to the 'Drinks list' tab;
* Rename the 'Edit settings' tab to the 'Drinks list';
* Add more adequate description into the plugin.xml file;
* Make the images more attractive with the fixed size;
* Add the 'Drink sent' message after the page refreshes..