The Ruby community has excellent documentation. Every gem has a GitHub repo with at least a Readme detailing basic usage and installation. But there are resources beyond GitHub readme's that many developers fail to utilize. If you find yourself stuck on a problem, take some time to check out these sites. Taking the time to learn about a system you use will provide valuable insight. You will be surprised how a problem that seems impossible to solve becomes trivial once you have a deeper understanding.
If you're reading this blog post, you probably know how to write Ruby code. But how many of us can say we know all Ruby has to offer. The Core API and Standard Library API has a wealth of information about the classes, methods, and modules available to you. It's important to know your Ruby version before diving in. Ruby has changed a lot over the year, and you don't want to be stuck reading old docs that don't apply to you. Next time you're unsure how something works, check out the RubyDocs.
2. Rails Guides
My go-to place for Ruby on Rails documentation is the Rails Guides website. This site is written more like a book than a reference. Next time you're struggling to understand a system in Rails, take some time to learn about the portion of Rails you’re using. Rails is a very complicated framework with many features. Don't try to reinvent the wheel when Rails might already solve your problem.
This site has a lot of great information about different technologies used to build web applications. I recommend you are familiar with the SQL, CSS and HTML section of the site. The SQL section has an excellent tool where you can write queries against a mock database. This is a great way to experiment with new syntax before trying to replicate it with ActiveRecord. The HTML and CSS reference sections provide descriptions and compatibility matrices that are helpful when understanding how and if something will work in a browser.
5. Your Database Docs
Most Ruby on Rails applications uses a Postgres or MySQL database. These database technologies share many similarities, but they also have differences. Understanding how your database server works will make a massive difference in your application's performance. Take the time to read about what makes your database unique. Never assume that a query will function the way you think. It only takes a minute to read the documentation to be sure.