I use Intellij IDEA Community Edition and I wanted to install the Ruby plugin, but it is only available for the full version of the IDEA, although distributed free license. How to install it in community edition version?
You answered your question already: you cannot use Ruby in IntelliJ IDEA Community Edition, the plugin won't work:
Supported only in Ultimate Edition: ... Ruby, JRuby ...
Source
As stated in a comment, you can get IntelliJ IDEA Ultimate for free (non-commercial use only) as a student.
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