How would you incentivize university students to write course reviews?

I'm a current university student and over the past few years, I noticed the course selection process was incredibly broken.

There's a university-wide course listings page, then a faculty-specific course listings page (e.g. a specific one for the business school, a specific one for engineering etc.). Each of the different course listings had different information, sometimes the university one didn't have the most up-to-date information so it wouldn't be able to tell you which professor would be teaching which session and you would have to refer to the faculty-specific one for that info.

To get reviews from other students, you would have to resort to RateMyProfessor and various Facebook groups. Course syllabuses were also not provided by the university, so the best hope we had of finding out what the curriculum is before selecting the course is asking friends that have taken it in the past to send the syllabus.

I built a platform that centralizes the information from the various course listings pages and lets students write reviews, as well as upload syllabuses for others to see. Students log in to the platform using Facebook authentication and can write reviews anonymously if they choose to do so.

Since launching the product, I've gotten good feedback and the social media posts about it have gotten lots of interaction. However, I've struggled to get people to actually write reviews. Any ideas on what I can do to incentivize students to write more?