创建，添加sdram

rt-thread/.gitignore

@@ -0,0 +1,53 @@
+*.pyc
+*.map
+*.dblite
+*.elf
+*.bin
+*.hex
+*.axf
+*.exe
+*.pdb
+*.idb
+*.ilk
+*.old
+*.crf
+build
+Debug
+rtthread
+settings
+documentation/html
+*~
+*.o
+*.obj
+*.bak
+*.dep
+*.lib
+*.a
+*.i
+*.d
+*.dfinish
+*.su
+#source insight 4 project files
+*.si4project
+tools/kconfig-frontends/kconfig-mconf
+packages
+dist
+rt-studio-project
+cconfig.h
+GPUCache
+
+#cscope files
+cscope.*
+ncscope.*
+
+#ctag files
+tags
+
+.idea
+.vscode
+*.code-workspace
+*.eide.*
+.history
+CMakeLists.txt
+cmake-build-debug
+*.mk