I figured it out. For anyone interested:
Go to System Preferences>Users and Groups>Login Items. You may have to click the padlock and enter your password.
At Login Items, click the plus sign. Navigate through folders to
Your home>Library>Application Support
Then scroll down until you find "com.unmarked.textsoap8.menu" and click on it. From now on, that file should open whenever you login or start your computer, putting the TextSoap icon in the upper right part of your menu bar.
