Extract a build_site method due to RuboCop warning.
Extract a build_site method due to RuboCop warning.

PSPDFKit-labs/jazzy,Kapeli/jazzy,Kapeli/jazzy,agentk/jazzy,pcantrell/jazzy,pcantrell/jazzy,realm/jazzy,1ec5/jazzy,pcantrell/jazzy,PSPDFKit-labs/jazzy,agentk/jazzy,1ec5/jazzy,Kapeli/jazzy,realm/jazzy,agentk/jazzy,1ec5/jazzy