docs: developer: add a section to build from source

# Conflicts:
#	developer/from-source.md

developer/from-source.md

@@ -0,0 +1,118 @@
+---
+layout: '~/layouts/Markdown.astro'
+title: 'Compiling from source'
+license: 'Apache-2.0'
+origin_url: 'https://github.com/go-gitea/gitea/blob/62ac3251fa545d32bdfc9ff824106b97ec63edbb/docs/content/doc/installation/from-source.en-us.md'
+---
+
+# Installation from source
+
+You should [install go](https://golang.org/doc/install) and set up your go
+environment correctly. In particular, it is recommended to set the `$GOPATH`
+environment variable and to add the go bin directory or directories
+`${GOPATH//://bin:}/bin` to the `$PATH`. See the Go wiki entry for
+[GOPATH](https://github.com/golang/go/wiki/GOPATH).
+
+Next, [install Node.js with npm](https://nodejs.org/en/download/) which is
+required to build the JavaScript and CSS files. The minimum supported Node.js
+version is 16 and the latest LTS version is recommended.
+
+**Note**: When executing make tasks that require external tools, like
+`make misspell-check`, Forgejo will automatically download and build these as
+necessary. To be able to use these, you must have the `"$GOPATH/bin"` directory
+on the executable path. If you don't add the go bin directory to the
+executable path, you will have to manage this yourself.
+
+**Note 2**: Go version 1.20 or higher is required. However, it is recommended to
+obtain the same version as our continuous integration, see the advice given in
+[Hacking on Forgejo]({{< relref "doc/development/hacking-on-forgejo.en-us.md" >}})
+
+## Download
+
+First, we must retrieve the source code. Since, the advent of go modules, the
+simplest way of doing this is to use Git directly as we no longer have to have
+Forgejo built from within the GOPATH.
+
+```bash
+git clone https://codeberg.org/forgejo/forgejo
+```
+
+Decide which version of Forgejo to build and install. Currently, there are
+multiple options to choose from. The `forgejo` branch represents the current
+development version.
+
+To work with tagged releases, the following commands can be used:
+
+```bash
+git branch -a
+git checkout v1.20.0-5
+```
+
+To build Forgejo from source at a specific tagged release (like v1.20.0-5), list the
+available tags and check out the specific tag.
+
+List available tags with the following.
+
+```bash
+git tag -l
+git checkout v1.20.0-5
+```
+
+## Build
+
+To build from source, the following programs must be present on the system:
+
+- `go` v1.20 or higher, see [here](https://golang.org/dl/)
+- `node` 16 or higher with `npm`, see [here](https://nodejs.org/en/download/)
+- `make`
+
+Depending on requirements, the following build tags can be included.
+
+- `bindata`: Build a single monolithic binary, with all assets included. Required for production build.
+- `sqlite sqlite_unlock_notify`: Enable support for a
+  [SQLite3](https://sqlite.org/) database. Suggested only for small
+  installations.
+- `pam`: Enable support for PAM (Linux Pluggable Authentication Modules). Can
+  be used to authenticate local users or extend authentication to methods
+  available to PAM.
+
+Using the `bindata` build tag is required for production
+deployments. You could exclude `bindata` when you are
+developing/testing Forgejo or able to separate the assets correctly.
+
+To include all assets, use the `bindata` tag:
+
+```bash
+TAGS="bindata" make build
+```
+
+In the default release build of the continuous integration system, the build
+tags are: `TAGS="bindata sqlite sqlite_unlock_notify"`. The simplest
+recommended way to build from source is therefore:
+
+```bash
+TAGS="bindata sqlite sqlite_unlock_notify" make build
+```
+
+The `build` target is split into two sub-targets:
+
+- `make backend` which requires [Go v1.20](https://golang.org/dl/) or greater.
+- `make frontend` which requires [Node.js 16](https://nodejs.org/en/download/) or greater.
+
+If pre-built frontend files are present it is possible to only build the backend:
+
+```bash
+TAGS="bindata" make backend
+```
+
+Webpack source maps are by default enabled in development builds and disabled in production builds. They can be enabled by setting the `ENABLE_SOURCEMAP=true` environment variable.
+
+## Test
+
+After following the steps above, a `forgejo` binary will be available in the working directory.
+It can be tested from this directory or moved to a directory with test data. When Forgejo is
+launched manually from command line, it can be killed by pressing `Ctrl + C`.
+
+```bash
+./forgejo web
+```

developer/index.md

@@ -12,6 +12,7 @@ their needs.
   - [Governance](GOVERNANCE)
   - [Sustainability and funding](https://codeberg.org/forgejo/sustainability/src/branch/master/README)
 - For contributors
+  - [Compiling from source](from-source)
   - [Developer Certificate of Origin (DCO)](DCO)
   - [Development workflow](WORKFLOW)
   - [code.forgejo.org](code-forgejo-org)