Add lsp support for ruby (#258)

lua/lsp/ruby-ls.lua

@@ -0,0 +1,15 @@
+-- If you are using rvm, make sure to change below configuration
+require'lspconfig'.solargraph.setup {
+    cmd = { DATA_PATH .. "~/.rbenv/shims/solargraph", "--stdio" },
+    on_attach = require'lsp'.common_on_attach,
+    handlers = {
+        ["textDocument/publishDiagnostics"] = vim.lsp.with(vim.lsp.diagnostic.on_publish_diagnostics, {
+            virtual_text = O.ruby.diagnostics.virtual_text,
+            signs = O.ruby.diagnostics.signs,
+            underline = O.ruby.diagnostics.underline,
+            update_in_insert = true
+
+        })
+    },
+    filetypes = O.ruby.filetypes,
+}