Merge pull request semaphoreui#59 from markuman/add-gitea-auth

add gitea documentation as openid provider

Author: fiftin

src/administration-guide/openid/gitea.md

@@ -0,0 +1,29 @@
+# Gitea config
+
+`config.json`:
+```json
+"oidc_providers": {
+        "github": {
+            "icon": "github",
+            "display_name": "Sign in with gitea instance",
+            "client_id": "123-456-789",
+            "client_secret": "**********",
+            "redirect_url": "https://your-semaphore.tld/api/auth/oidc/github/redirect",
+            "endpoint": {
+                "auth": "https://your-gitea.tld/login/oauth/authorize",
+                "token": "https://your-gitea.tld/login/oauth/access_token",
+                "userinfo": "https://your-gitea.tld/api/v1/user"
+            },
+            "scopes": ["read:user", "user:email"],
+            "username_claim": "login",
+            "email_claim": "email",
+            "name_claim": "full_name",
+            "order": 1
+        }
+}
+```
+
+In your `gitea` instance, go to `https://your-gitea.tld/user/settings/applications` and create a new `oauth2` application.
+As redirect URI use `https://your-semaphore.tld/api/auth/oidc/github/redirect`.
+
+Authentication works fine. But "Name" and "Username" does not recieved correctly. The username will be a unique ID in semaphore and the name will be set to "Anonymous", which is changeable by the user itself. The emails is mapped correctly.