As a new (and excited) user, I too had this issue when trying to jump in ASAP to “kick the tires” with little to know knowledge of what to expect or how to do anything within the Ratel browser. The source of this initial confusion was when I hit the ‘Adding Indexes’ section of the Getting Started page (https://docs.dgraph.io/get-started/#adding-indexes). The basic instruction above on that page says to just copy/paste between the single-quotes if you are not using curl and want to work within the Ratel browser.
The issue seems to be that the curl url includes the ‘alter’ keyword (? suffix) and there does not appear to be anywhere in the Ratel browser for pasting and running this schema altering statement. Fortunately I was excited enough to keep poking around and stumbled on the Bulk Edit panel in the Schema tab and directly edited the entries there to include the alterations that would be done by this Getting Started curl expression.
Two possible solutions: 1) Update the Ratel Schema tab UI to include a panel to paste and run schema altering statements or (at least) tweak the instructions on the Getting Started page to explain the way to do the alteration within the existing Ratel browser.
Keep up the great work… As a Neo4j expat, I look forward to using this exciting technology and being a member of the community.